Sunday, July 31, 2011

Where does Lightroom keep changes?

Question

I've imported some raw images from camera and made changes. When I close and reopen LR I can still see the changes, but my original important RAW file is intact. So I'm curious, where/how LR keeps my changes on top of RAW file? Can I make my changes on imported RAW file? Say want to crop imported file and keep just cropped version.

Answer

Lightroom does not make changes to the original file. It stores the actions of each edit in the LR catalog. When you Export and image to say a JPEG, LR performs each of those actions, creating a new file, in this case a JPEG. It never alters the original. The RAW file isnt really an image, but data that was recorded by the sensor. You see an image in preview because the RAW file actually stores a small JPEG preview image within the file. So 'cropping' the RAW isn't meaningful. You instead use the RAW data to create an image that you can crop as your final output. The output can be JPEG, TIFF, PSD, DNG, etc.

The catalog location can be found by looking under Catalog Settings.

You can also ask Lightroom to store these same edit actions in a 'sidecar' file, which will be stored alongside (in the same directory) of your RAW image, by selecting "Automatically write changes to XMP" in the Metadata tab of Catalog settings.

Can anyone recommend a telephoto lens for a Sony DSC-H3?

Question

I have a Sony DSC-H3. I'd like to buy some new lenses for it for experimentation purposes. Specifically, I'd like to get a telephoto lens. The only issue is, I can't figure out which one to get. The official Sony one has been discontinued, and I'm seeing conflicting reviews for a few possible candidates on Amazon and Ebay.

Does anyone have a suggestion for a telephoto lens?

Thanks,

Answer

The Sony DSC-H3 is a superzoom camera with a permanently-attached lens. You can't really get new lenses for it in the same sense one might with an interchangeable-lens camera. There are some things sold as telephoto lenses for such cameras, but really they are "teleside converters" — secondary lenses which attach in front of the permanent lens. I don't have any specific purchase advice, but will note that such a lens is likely to add aberrations and reduce sharpness, particularly if it's cheap. You might get okay results, but you might actually do just as well by just cropping and enlarging.

If you're seriously interested in getting some new lenses for it for experimentation purposes, I highly suggest you start considering an interchangeable lens system — either a DSLR or one of the new mirrorless camera systems like Sony's NEX. This will have more sticker shock, but if you really want to experiment with photography, you're going to want something like that eventually anyway. Might as well start sooner rather than putting money in a different direction.

Is there a product which provides super-bright continuous light in a small package?

Question

I met a friend of a friend last night who used to be a pro photographer. He had this gimmick that he said was kinda home-made by some shop owner in Singapore. I wish I took a pic of it, but I forgot. I will try to explain as best as possible.

It was basically a super bright LED, usually used for floor lighting or some such, housed in a tiny box that's about 1 inch × 0.5 inch × 0.5 inch, powered by either AA or AAA batteries, with an on-off switch, and most importantly the LED itself is diffused by a small square plate of I-don't-know-what material. Continuous lighting that's extremely portable, can fit three of them in one palm, and runs a couple hours on batteries. Is there any product like this sold anywhere, online or otherwise?

Answer

At that size it would probably be using a CR123 type battery. Two of them in series will light up extremely bright LEDs. Ones you can get like a surefire type body will last about 20 hours on a pair of those but are only bright enough for "seeing" and won't light up a small room for photography.

Of course you can go nuts with with a diy led driver that pushes an led module with more than 5 watts. Taking a glass plate and grinding into a makeshift lens and sandblasting will give you a diffused refractor that you can reverse for wide or narrow beam in it's most simple form or you can even make a rail with the lens in a housing so you can "zoom" the light angle. If you only want diffusion then cut out an acrylic piece and sandblast or hand sand it down.

I built something like this for a few different projects, it's not hard if you can source all the parts. A module that's less than 10 bucks can shoot out 300+ lumens which is more than most Surefire weapon lights...

The most economical power supply would be li-ion 18650 sized batteries. They look like AA size but slightly bigger; almost all laptop batteries are composed of a bunch of these stuck together in a slab.


Here's a sample diy light source

you could build- it will provide slightly less than 700 lumens at 6500k color temperature and 70 CRI quality and will probably fit in an enclosure the size of a Rubiks cube. Runtime is 8 hours This is similar to the box you described earlier; it will light up a room with no problem.

for example, this photo shows a flashlight with "only" 500 lumens, so now you know what the device is capable of.

part / description / qty / approx price / source

  • 5 watt led module / with heatsink / two of these / ~ $14 / superbrightleds.com
  • LG 2600mAh li-ion cells / 18650 size / six / ~ $45 / batteryjunction
  • 1.0 ohm 1w resistors / vishay dale or milspec / two / ~ $3 / mouser
  • diffuser / sanded or blasted acrylic, maybe glass / one / ? / hardware store
  • enclosure and switch

here is roughly what it would look like:

link to diagram


There are various ways to adjust the lighting angle and intensity.

Angle

By having the leds inside a can on a "rail" system with a parabolic reflector, you can adjust between a wide angle light or a spot light.

this photo shows what I'm talking about.

Light Intensity

There are three ways to adjust light intensity:

  1. Use paper gobo or something = waste of power, easy, free, lower intensity

  2. A switch to halve the voltage = more wiring, 7v led may not be efficient at 3.6v, lower intensity

  3. Have four 5w leds instead of two, wired to turn on 1 or 2 or 4 at a time = jungle of wires, efficient you get three intensity settings:

    • 350 lumens@ 20 hours

    • 700 lumens@ 8 hours

    • 1400 lumens@ 3.2 hours

Obviously the third is the best. It isn't very expensive because you are only adding two more leds; most of the money is in the battery and charger. Labor is another story :P


Recharge the batteries; CAUTION

You'll note that I haven't mentioned how to recharge the batteries. It depends on whether you want to use an external charger with battery slots to charge each 7.2v pair (very tedious) or will be keeping the batteries inside(convenient and safe) and using a "battery pack charger"(like a normal charger but doesn't hold batteries, it has wires instead that you have to lead to something to charge.)

Either way each pair of batteries will need a protection device attached to prevent dangerous overcharging and a damaging over-discharge when low on juice.

The safest way to charge the system would be like this

Wall -> this charger, set to 8.4v -> the light system's three jacks -> each jack to the respective battery pair's protection board

You need three dc jacks unless which is safest method, using switches or other random ways to save on wiring may result in explosion.


The whole kit with three power settings and best charging method will cost $100 ~ $150+ including random stuff like wires, enclosure and switches.


a word on safety

This whole contraption may explode if you are not not careful, or even randomly. The 15" MacBook Pro also has six cells and it runs for 7 hours so you can sort-of imagine how big the explosion will be, lol.

How does “sweep panorama” compare to traditional montage?

Question

Newer Sony cameras offer "sweep panorama" mode where you just pan the camera and it stitches the panorama picture in the camera. This function is starting to appear in models from other manufacturers too (can't find the relevant link at the moment).

Apart from the obvious limitation to one picture height/width (one cannot create 2xN or Nx2 panorama in this mode) - can anybody tell how sweep panoramas compare to traditional panorama montage? Is the result comparable/better/much worse?

Answer

I tried a model like this in the store, both horizontally and vertically. I was not satisfied with the quality. The particular model that I tried used seemed to be using the HD video imaging pipeline to do its stuff. Also, when used vertically, it required you to change the orientation of the camera by 90deg. In the end, the small dimension on the pano was always 1080. You can do way better than that with stitching with a hand held p&s that has man exp and focus.

So my advice is try before you buy.

Is there a “How do they do that?” site for learning image post-processing techniques by examples?

Question

I often see really excellent photographs that seem to have been adjusted in photoshop or something like that. This includes even pictures that seem to be from someone's vacation or travel.

Is there a site where they show a great photo (lets say daily) and an explanation of how the effect was achieved? I want to learn by seeing a photo I love and then seeing how it was made.

Answer

Post processing in Photoshop (and similar tools) are one of the benefits of digital photography. With quite simple means you can edit the files from your camera, improving the final product. For some it's almost as important as taking the actual shot.

There are many ways to learn "photoshopping" (or retouching). I cannot direct you to a particular web site but I know many books covering this subject. There are books on portrait retouching, HDR and of cause general editing in Photoshop.

Scott Kelby is the number one selling author in the field of photography. You can browse through his collection of books (and books from some of his colleges/friends) on Kelby Training Books.

Of course there are web sites too, but if you would like to learn the art of photo editing I would recommend a book.

What do “Frontfocus” and “Backfocus” mean?

Question

I've read those terms in a couple of lens reviews, and not even Wikipedia has an article about it.

So my questions are:

  • What is back/frontfocus?
  • What causes back/frontfocus?
  • Is there any preventive measure to avoid getting back/frontfocus?

Answer

Front focus is when the lens and camera focus in front of your intended focus point. Your subject will look slightly out of focus and something in front of them will be razor sharp in focus.

Back focus is correspondingly when something behind them is in focus, instead of your intended subject.

As to why.. it could be mis-aligned, mis-calibrated equipment. It could be you or it could be your subject. You or your subject could have moved slightly after focusing and this would also cause front or back focus.

In terms of why it would be this way for the equipment:

  • Things may be out of spec from the factory, due to poor QA.
  • Things could be in an acceptable QA range, but your combination of camera and lenses could be at opposite ends of the acceptable range.
  • Your autofocus could be not properly functioning due to a software issue (this seems to be the case for the Pentax K-x camera with tungsten light sources...go figure).

There's a host of why, but most of them boil down to something being not quite calibrated, aligned, or working 'properly'.

Modern choices to fix it usually include one of three options that I'm aware of:

  1. Send your camera and lens to the manufacturer to be 'fixed' or calibrated.

  2. Your camera may have a global adjustment in which you can tell it to always adjust its autofocus front or backwards by a small adjustable amount.

  3. Your camera may have a per lens adjustment in which the camera will remember that this lens always needs a certain small adjustment that you provide in order to function properly. (Usually up to some reasonable number of lenses.)

Which of these is an option, typically depends on the 'level' of camera you have. More entry levels (like my Nikon D3100) have no adjustment options. The Pentax K-x (mid level), for example, offers a global adjustment and the Pentax K-5 (mid-upper level) offer a per lens adjustment.

Why doesn't narrowing the aperture have the same effect as lowering the flash power?

Question

I have a small doubt here. I'm no strobist and just got my first flash (Canon 430ex II Speedlight). While I was playing around, I found that narrowing down the aperture DOES NOT have the same effect that lowering down the power of the flash has. I'm using reflective umbrella here to bounce the flash back.

Logically, narrowing down the aperture should lower the flash power reaching the sensor and hence darkening the image. But it doesn't have the same effect that lowering down the power does. And yes, I've tried it in both TTL and Manual modes.

Answer

Narrowing the aperture will reduce all light coming in to the sensor, including light coming from the flash itself and ambient light.

Reducing the flash power changes the ratio of flash light to ambient light. True, it will reduce the overall amount of light, but the reduction is not as evenly distributed as when you reduce the aperture (which reduces everything).

Taken to the extreme: if your flash power was very low and your ambient extremely high (such that the ambient dominated the exposure), lowering your flash further still would have no effect. Think, for example, of a low-power flash on a very sunny day. You'd have to look closely to notice any reduction in flash power, though aperture will have a very significant effect.

So, if ambient light is a significant factor in your exposure, then you will indeed get different results by changing one or the other.

Now, if you were using a high shutter speed to completely eliminate the effect of ambient light, then there might be finer details to discuss here. Perhaps you could post a photo of your shot and describe the details of your exposure & lighting setup?

Saturday, July 30, 2011

How can a sunset photo have pink and purple colors?

Question

I was browsing, and found this gem, which has distinct hues of pink and purple. I am curious so as to how the photo has shades that it has. Was it edited later? Do such colors really occur while the sun sets?

Answer

From the looks of it there is also a bluish cast to the ground on the bottom of the photograph so I wouldn't be surprised if they used a blue graduated filter inserted so the darkest part of the filter was at the bottom of the frame. Likewise, a red graduated filter would also make the sunset more intense and could be inserted such that the deepest red is at the top of the frame.

Looking though the other photographs in their gallery I notice that the color schemes to keep appearing so it is unnatural that they are all naturally occurring sunsets and in one of the photographs he confirms that he uses Lee filters when he takes the photographs.

What precautions should I take when taking a camera into humid conditions?

Question

My camera's manual warns about sudden changes in temperature, but there are a few cases when I can't see how to avoid this.

These include entering a reptile house in a zoo, or a trip to tropical house such as in the Eden Project, where the outside temperature is 15° C and inside it's 38° C.

On a recent trip, I did not take my SLR but I saw may others with them although the lenses were all steamed up initially and unable to get a shot.

Will the sudden change in temperature harm the camera beyond just fogging up the lens, and are there any precautions to take against this possible harm?

Answer

Condensation is the biggest risk, and prevention is always better than cure. One thing I do prior to entering such environments is to place a lens cloth over the front element, and heat it with the heat from my hand prior to entry -- the target is to get the front element above the dew point for the area you're going into.

With the specific case of the Eden Project, the trick is to go into the arid Mediterranean house first where the humidity is lower than the rainforest house (but the temperatures are generally similar).

If anything, I'd suggest SLR (and bridge) cameras are easier to remove condensation from the lens (but it would take longer to warm through). It would be a "very bad idea" to change a lens inside an area with elevated humidity, as humid air could then condense all over the place.

It is worth remembering that some SLR cameras have professional quality weather sealing

What tool produces better quality jpeg: Lightroom or Imagemagick?

Question

I'm using Lightroom for photo workflow. At the end of it, I would like to have the best JPEG I can get, basically two options to choose from: - export from Lightroom to JPEG, using the 100% Lightroom quality - export from Lightroom to TIFF and converting to JPEG with ImageMagick

I know that neither 100% is really 100%, nevertheless, I'd like to choose the better options, which one is closer to the original file. Have someone measured the difference between the two? I've seen a thread about how to compare the difference, but never seen reasonable measurements.

Thanks,

update: I'm shooting in raw, using dng, exporting different sizes. The question is: what tool produces better quality jpeg: lightroom or imagemagick?

Answer

I have both, so I ran a quick test for you.

Firstly, here's the original DNG. It's a snap of mine, converted from Nikon NEF by Ligtroom, no editing.

I then exported it with Ligtroom, same size, no sharpening, 100% JPEG quality, and no edits. Lightroom Version

(You can download it from here for pixel-peeping)

Then I converted the DNG through ImageMagick. Again, no edits, 100% quality:

ImageMagick Version

(Here's the downloadable location)

You be the judge which gives the better export. However, note the following:

  • The Lightroom version has been modified. Not only is the exposure different, but it's very slightly warped relative to the ImageMagick version. I think there might be some lens correction going on. If there is, I can't find it; all my "Develop" settings are at default.
  • The DNG is 8.6MB. Ligtroom's JPEG is 7.3MB: not a very significant compression, but that's what you get at 100% quality. Imagemagick gave me a 14.2MB file.

Here's my take-away from this experiment: It doesn't matter.

  • You're going to want to edit your photos. Your image editing will probably affect your results more than your choice of JPEG conversion tool ever will.
  • You'll want to increase your JPEG compression by reducing the quality setting. Otherwise, you'll get files with barely any compression at all; at that rate, why not go TIFF or PNG? By increasing the compression, you're going to lose quality, and it will probably be more significant than the mere choice of tool.
    • This is especially significant with ImageMagick giving the wacky larger results than the DNG; it blows that option out of the water.
  • How big of a deal are the quality differences anyway? You'll have to really pixel peep at full size to see any changes. If you get obvious visual differences (like my exposure shift), the differences due to conversion will be insignificant.

What kind of dose can you expect from a radioactive lens?

Question

I read that lens makers used to use radioactive glass to increase the refractive index property of their lenses.

How radioactive are they?

Here are some example dosages; where would looking through the viewfinder for an hour fit?

http://xkcd.com/radiation/

example radiation doses example radiation doses

Answer

The article in rfusca's answer includes some references: The Aero-Ektars,by NASA scientist Michael Briggs); Radioactive Materials in Camera Lenses from the Health Physics Society, an organization focused on radiation safety; and Thoriated Camera Lens (ca. 1970s) from Oak Ridge Associated Universities's professional training on radiation safety.

From the ORAU PTP article:

Measurements have indicated that the exposure rate at a depth of 10 cm in the body of an individual carrying a camera containing 0.36 uCi of thorium would be approximately 0.01 mrem/hr. Based on this value, NUREG-1717 calculated that a serious photographer might receive an annual exposure of 2 mrem. This assumed that the photographer carried the camera 30 days per year and for 6 hours per day. They also estimated an exposure of 0.7 mrem per year for an average photographer. If the camera lens contained the maximum permitted concentration of thorium (30%), NUREG-1717 estimated that the aforementioned annual doses could triple.

This puts the "6hrs/day for a month" usage at about the same as getting a chest X-ray — or, one little green square on the xkcd chart. Or to put it another way, using the lens six hours a day for a year would be the same as taking three round-trip flights from one US coast to the other in that year. Not completely trivial, but not something people normally stress about. And that'd be really heavy usage.

The articles indicate that exposure to the eye might be a greater concern than overall dosage, particularly if you happen to have thorium in an eyepiece (unlikely for general photo equipment). So you might decide to spend a little less time holding the camera right to your eye than you might otherwise.

How do you make the most stunning sunrise and sunset photos?

Question

I've been lucky on a few occasions, but I often struggle with capturing awesome sunsets. What can I do to remove the element of luck and get more consistent results?

Additionally, is it possible to tell if a sunset set is going to be particularly striking far enough in advance to plan to get to an awesome location in time?

Answer

I've done well with the exposure rules from "Understanding Exposure" by Bryan Peterson.

Basically, use manual exposure. You probably want everything in focus, so a high f/stop number (ie small aperture) will help you achieve that. That may mean you need a long-ish exposure, so a tripod would help (and will be essential if you want to use HDR techniques).

To set the exposure, choose spot metering mode, point the camera up at the sky, and set the aperture and time so that the sky is correctly exposed. Then recompose and take the photo. Review the picture and adjust the exposure if it is too dark or light for the effect you want. This photo was exposed for the sky:

Sunset exposed for sky

Alternatively, if there is a lot of water in the picture you may want to expose for that. Water will be darker than the sky, even with the reflected sunlight. So do the same as above, but point the camera at the water to set the exposure. This photo was exposed for the water in the foreground:

Sunset exposed for water

Which you prefer is up to personal preference and the objects you have to work with in the composition. On the non-exposure parts, I've nothing to add to what the others answers say.

Edit: I've decided there is one more thing to say. The light can change very fast, so if it looks beautiful take a picture now. Then recompose and take another, or play around with your metering and take another. Or wait a bit and see how the light develops. But only after you've got at least one shot of it - the light can go from stunning to boring in 30 seconds or less sometimes, so it's better to end up with a shot of the beautiful light caught in an OK way than a technically perfect shot after the light has died.

Friday, July 29, 2011

How do I properly expose dark scenes containing bright light sources?

Question

I'm new in photography, however I have some basic knowledge of exposure, aperture, etc.

I own a Nikon D7000. The issue I've found in number of pics I've taken (in P mode) is that whenever the scene is relatively dark and there is a bright contrasting lighting source (bulb or sky), then I get too dark of a picture overall. Here is one example.

What I can do to make light source be darker and the rest of dark scene be brighter?

enter image description here

Answer

You're asking the right question, "How do I properly expose...?" Put the emphasis on the "I" part of that. If you are using "P" mode then you are not determining the exposure. Your camera is. And your camera thinks it is taking a snapshot of your Aunt Mathilda at Christmas, and has no idea that you are trying to do something creative. So in cases like this you need to take control, meaning switching to "M" manual mode, or at the very least, playing with camera features like "exposure compensation" or "exposure lock" or "spot metering". Look these up in your camera's manual.

Generally, you want to look at a scene like this and decide what parts of it you want to be be the well-exposed. Presumably in this photo you wanted the worker to be be a little brighter, so you could see more detail. These could be done a few ways:

  1. Take a photo like you did, then examine the results and maybe the histogram and take another shot with positive exposure compensation.
  2. Zoom in so you are excluding the brighter lights
  3. Meter the shot when centered below the person, with the lights excluded and then either use exposure lock (if your camera has it) or set that exposure manually after reframing the shot the way you want it.
  4. Enable spot metering so your exposure is determined by the very center of the frame, giving less weight to the lights on the side.
  5. Bracket your exposure, so you automatically get shots 1 stop faster and slower. This also allows you to do some post processing, even HDR.

Are there GIMP plugins that allow one to view and edit EXIF data?

Question

Does anyone know if there is a plugin available for the GIMP that will let you view and edit all the EXIF information associated with an image?

Answer

To be honest I'd probably use some photo management software for managing the exif data. It's likely to be more powerful and allow for various batch operations. If you're on Linux, you could try one of the ones listed under this question.

But if you insist, you could try

Don't know if that's enough for you, but as I say, I'd use something else for exif manipulation.

What is the best technology for large, permanent digital printing?

Question

Few questions:

  1. What is the best printer/plotter for printing large format images (best means best visual quality)
  2. What material and inkjet is the most permanent?

I'm thinking of printing images and I want to get the best posibble quality. Image dimensions would be from 0.5m to 2m (or even more).

How about this printer: http://www.usa.canon.com/cusa/consumer/products/printers_multifunction/professional_large_format_inkjet_printers/imageprograf_ipf8300

...or similar ones? Do such printers provide the best print that is available on market?

Thanks,
Ile

Answer

The Canon iPF 8300 is one of the more advanced large-format, commercial printers available on the market today. It is indeed designed to produce the highest quality large format prints possible. The key thing about the 8300 is that it uses Lucia EX ink, which is a very new pigment ink formulation specifically designed to produce a wide gamut on print. Similar to Epson's Ultrachrome HDR ink, the solid color gamut reproducible by Lucia EX supports over 90% of the Pantone Solid Color matching system on supported paper types. The Epson 7900 and 9900 are Epson's counterparts, and offer up to 98% Pantone on a specific paper type and at maximum DPI.

Ink is the primary factor that affects print output, quality, and gamut. If you intend to create prints that most accurately reproduce color and render fine tonal gradients smoothly, I highly recommend a Canon printer that supports Lucia EX ink, or an Epson printer that supports Ultrachrome HDR ink. For the widest gamut possible on a variety of unique paper types, such as metallic, you might want to look at the Epson Stylus Pro WT7900. This printer uses a new white ink, part of the Ultrachrome HDR + White ink set, which allows more control over highlight tones and possibly even white point. When it comes to HP printers, they are currently not as competitive in the area of ink as Canon and Epson are. Their Vivera pigment ink seems to date back to 2006, which is pretty old by current standards. Canon Lucia EX was released in March 2010, and Epson Ultrachrome HDR was released late 2009, so these brands have a considerable edge over the competition when it comes to accurate color reproduction.

As for which paper type is best...thats a much more subjective area. Both Canon and Epson wide-gamut, large format printers only support their maximum gamuts on a small range of their own brand of papers. A wide gamut is still supported for other papers, including off-brand papers, however they can't guarantee 90% Pantone Solid Color coverage on every paper type (at least, not yet.)

There are several key factors in choosing a paper for your prints. Not every type of photography looks the same on any type of paper, so you need to choose paper types that compliment the type of photography you are printing. Some types look best on glossy or luster papers, some require bright white or pure white, other types look best on natural papers with warmer white points. Some experimentation will be necessary to identify which paper types, finishes, and white points best compliment the type of photography you are printing. In this area, Epson offers more brand name papers than others, however their papers are not necessarily the best, either. Canon offers a fairly broad range of paper, however much of it is manufactured by Hahnemuhle. There are also plenty of third party papers from manufacturers who have been in the business for hundreds of years, including Hahnemuhle (and Harman), Moab, Museo, Ilford, Breathing Color, etc.

Certain factors of a paper affect the reproducible gmaut when printed on. One of the primary factors that affects gamut is the white point and white brightness of the paper. A "purer" white, one that falls around 5500K-6500K, will expand the reproducible gamut as well as maximum tonal range, as it is a purer, more "white" white. Cooler whites (that show up almost blue) or warmer whites (that show up with more orange or red) will reduce or shift the reproducible gamut, as the paper itself will affect color reproduction. Black and white prints tend to look best with a pure white paper, unless you want the artistic or warming effect of a "natural" white paper (which is what most matte fine art papers provide). The brighter the paper, the greater the tonal range is likely to be. Some papers include optical brighteners, which use UV sensitive material that absorbs UV light and emits light in visible wavelengths. Gloss, semigloss, luster papers often have optical brighteners, which can help improve gamut and tonal range...however since they have UV reactive components, they often require a specific kind of lighting to reproduce color correctly.

Another aspect of print quality is paper texture. Not all paper is equal in this regard, and there are a variety of materials, including wood, cotton, bamboo, sugar cane fibers, used to create the printable surface of a paper. Certain fiber types bring out the most in certain types of photography, and certain textures can help add a bit of artistic flare.

In my personal experience, I've found that gloss or luster papers are best paired with portraits, pure white papers are ideal for black and white prints, and photo rag (cotton) papers with a natural white produce superb landscape prints. I personally try to avoid papers with optical brighteners, however such papers may serve your specific type of photography well, so I would experiment.

What is the best approch to photographing a mirror or other highly reflective surface?

Question

I have been asked by a client to take some product photographs of some vintage mirrors that they would like to sell and I am struggling with getting good clear shots of the mirrors. As such, what is the best way to approach photographing them such the mirror does not appear to be washed out or contain any unwanted reflections?

Answer

As Rob said, a tilt-shift lens is ideal.

I talked to a product photographer who specifically mentioned it's use. Basically, you position the camera on a tripod just to the left or right of the mirror so it's out of the reflection. With a normal lens it will be obvious that it's taken at an angle but by using the shift function of the lens you're able to correct the perspective distortion (just like an architectural photographer) so it looks as if the photo was taken head-on.

This article has an example shot: http://www.popphoto.com/how-to/2011/05/complete-guide-to-tiltshift-photography?page=0,3

Why can't I take a photo in dark with auto focus, manual mode?

Question

I'm dorking around with a Nikon D80 and I am a total beginner. I am trying to shoot some light trails but the darn thing doesn't even take a picture. I am in manual mode with the bulb setting. For some reason, when I hold down the button, it does not take a picture. I can hold the button half way for the lens to auto focus (is that what it is doing when it is moving?), but when I press down all the way, the camera refuses to take a picture. When I go back to automatic mode, it happily takes a photo. What am I doing wrong? Thanks!!

Edited post: I am thinking it has something to do with how far/close the subject is. If there is something close, the camera doesn't want to take a picture, but if there is nothing right in front of it, it will take a pic in manual mode... (Generally hypothesizing right now.)

Answer: I think I found out what is wrong. The lens was on auto focus. I guess I had to change it to manual to use manual mode..... It works now (taking a pic of something close up that is..) Could anyone give a more detailed explanation as to what happened here? :)

Answer

Re. your answer - you don't have to have the focus set to Manual just because you're in Manual mode, but autofocus systems generally don't work in the dark. Therefore the camera will fail to focus and refuse to take a picture. By switching to manual you remove that problem.

Switching to Auto mode may allow autofocus because it turns the AF illuminator on. Autofocus works by splitting the image coming through the lens and then calculating the focus needed to recombine it. If the image is too dark, the camera can't 'see' what it's splitting and recombining, and so it will fail to focus. The AF illuminator lights up the scene so the camera can make its decision, but it's usually turned off when in the priority or manual modes.

When lighting painting, it's best to pre-focus manually with the lights on, then leave it on manual and turn the lights off.

Why can't I take a photo??

Question

I'm dorking around with a Nikon D80 and I am a total beginner. I am trying to shoot some light trails but the darn thing doesn't even take a picture. I am in manual mode with the bulb setting. For some reason, when I hold down the button, it does not take a picture. I can hold the button half way for the lens to auto focus (is that what it is doing when it is moving?), but when I press down all the way, the camera refuses to take a picture. When I go back to automatic mode, it happily takes a photo. What am I doing wrong? Thanks!!

Edited post: I am thinking it has something to do with how far/close the subject is. If there is something close, the camera doesn't want to take a picture, but if there is nothing right in front of it, it will take a pic in manual mode... (Generally hypothesizing right now.)

Answer: I think I found out what is wrong. The lens was on auto focus. I guess I had to change it to manual to use manual mode..... It works now (taking a pic of something close up that is..) Could anyone give a more detailed explanation as to what happened here? :)

Answer

Re. your answer - you don't have to have the focus set to Manual just because you're in Manual mode, but autofocus systems generally don't work in the dark. Therefore the camera will fail to focus and refuse to take a picture. By switching to manual you remove that problem.

Thursday, July 28, 2011

In Nikon D90, what settings apply for what mode?

Question

I bought Nikon D90 yesterday. How do I know which custom settings apply to what mode, i.e Auto, M, P etc?

Answer

The program modes (P, A, S and M) affect the shutter speed, aperture and ISO selection only as far as I know. Choosing one of these will not auto select a focus or metering mode. The camera will choose what it thinks is a sensible combination of aperture, ISO and shutter speed, but you can override this using the rear thumb dial.

The scene modes (sports, portrait, close up, landscape, etc), on the other hand, do affect the metering and focus modes, and in fact lock these down so that you can't change them. If you are in manual mode and have chosen spot metering, then switch into any scene mode, the camera will switch to matrix metering. Sports mode will select AF-A autofocus mode (why not AF-C? who knows). I think the scene modes also force white balance to Auto! Scene modes will also set Picture Controls and prevent you from using exposure compensation.

I would recommend you read up about the autofocus (AF-C, AF-S, AF-A) and metering modes (Matrix, spot, center-weighted), white balance and selecting focus points: how to set them and when to use them (a bit too much to go into here). Then use the program modes, like S (shutter) when shooting sports or moving objects, A (aperture) for most other things, and don't use the scene modes. Then you'll be able to use exposure compensation, set your white balance and so forth and not worry if the camera is doing something you don't know about.

If you want detailed information on all these combinations of settings, Thom Hogan has a good guide. The D90 manual also covers some of this.

What do the AF-A, AF-C, and AF-S autofocus settings mean?

Question

My camera has these settings for autofocus, and I don't know what they mean. I suspect "A" is "Auto", and "C" is "continuous", but I have no idea what "S" is.

Answer

This link explains it well. Paraphrasing the article:

  • AF-C (AF-continuous or servo mode) is used for photographing moving subjects.
  • AF-S means single shot and is used for subject that is stationary.
  • AF-A is where the camera decides whether the subject is moving or not and tries to alternate between the servo and single shot mode accordingly.

How can you write/convert Picasa's People tags to the EXIF data?

Question

I use Lightroom for my workflow, and I tag photos with people's names so that I can find them faster.

Since Lightroom doesn't have the "Faces" feature, I want to use Picasa's People feature for this purpose, but I don't want to work constantly with both of them. I'd rather use Picasa to tag the photos with the name tags every time I import new photos, and come back to Lightroom for the rest.

I couldn't find a way to make Picasa actually "tag" the photos (in the EXIF) with the people's names. Is there any plugin / script / ... that can make this happen?

Answer

Picasa stores faces information in the .picasa.ini files:

[test.jpg]
faces=rect64(1eb1929f885e),15441a598f9f1866
backuphash=29866

The id numbers can be found in the contacts.xml file which stores all the contacts of your pictures:

<contact id="15441a598f9f1866" 
  name="Test Test" 
  display="Test" 
  modified_time="2010-05-13T17:19:46+01:00" 
  sync_enabled="0"/>

Several programs can read these files and modify the EXIF accordingly. For instance:

What do AF-A, AF-C, and AF-S mean?

Question

My camera has these settings for autofocus, and I don't know what they mean. I suspect "A" is "Auto", and "C" is "continuous", but I have no idea what "S" is.

Answer

This link explains it well. Paraphrasing the article:

  • AF-C (AF-continuous or servo mode) is used for photographing moving subjects.
  • AF-S means single shot and is used for subject that is stationary.
  • AF-A is where the camera decides whether the subject is moving or not and tries to alternate between the servo and single shot mode accordingly.

How do I know if a lens is genuine?

Question

I'm in Times Square shooting the Imagine Cup event, and several people said that to fix my shot, I would need a faster lens. Just for the hell of it, I went across the street to a photo shop to see if they had the lens, and what they would be willing to sell it for. The price they quoted though, is kind of unbelievable. Particularly given that on Manhattan Island I would expect pretty much everything to be more expensive.

I'm concerned that I would be walking right into a ripoff of a refurb'd, used, or "grey market" lens. But I don't know enough about what the legitimate lens looks like to tell. What things should I look for to distinguish a legitimate lens from a fake one?

Answer

Both refurbs and "grey" lenses are genuine. The only way you could tell the difference from a US made new one is if you had a list of serial numbers for each category.
Fakes are more easy to spot, will usually have clearly inferior materials and often (deliberately) missspelled brand names (so the seller can claim he wasn't trying to scam you, you made a mistake in misreading the name. Something that may not hold up in court when the actual trademark owner sues, but will hold up (probably) if you'd sue). Think fake "Louis Vuitton" bags sold as "Louie Vutton", Nikon might be changed into Nikkon. For the very best fakes though, it'd take good knowledge of the real thing to tell the difference. But this being Manhattan (New York in general, long home to very shady camera stores) I'd not trust anything offered at much under manufacturer RRP.

What are the optimal JPEG settings for Facebook photos?

Question

Every time I upload a photo to facebook I'm disappointed; the photos just look really bad. What size do you recommend, dpi, etc? If it helps, I'm using lightroom.

Answer

I use 72 dpi - Resize to fit checked - 700 pixels - Long Edge - Don't Enlarge checked. Sharpen for Screen - High. Quality 100 - sRGB - JPEG.

Can you help me choose filters for a Canon PowerShot SX30 IS?

Question

I would like to buy Canon PowerShot SX30 IS camera and also would like to buy a filter to protect its lens.

I would like to have complete set of filters ranging from polarized, starburst, UV, red one for sun shots. However i learn that they could be expensive.

Also i would like to know whether after fitting the filter on top of lens does the lens cap still works? Or its like that i have to put on filter each time i remove the lens cap?

Please let me know which one i should buy and what options i have. Web links and information could be great help.

There appears to be two choices 67MM ring and 58 mm ring Does it fit and suited for this camera? Thanks.

Answer

I think you need an adapter, like the one from lensmateonline.com, first (I got one for my SX10IS and was very happy with it). There is a FAQ on that page that should answer most of your questions.

You'll probably need a new lens cap and lens hood.

Personally, I'm not a fan of leaving a filter on the lens all the time to protect it; there are a lot of opinions either way on this subject, you could probably waste a lot of time reading about the pros and cons. A circular polarizer and an ND filter (probably a 3-stop (sometimes called 8x)) are my two favorite filters.

You do NOT need a circular polarizer for your camera. A linear polarizer will work fine. You only need a circular polarizer if you have a DSLR (since the DSLR has a different light path to the viewfinder than to the sensor). Learn from my mistake, where I spent an extra $20 to get the circular polarizer when I didn't need it :) (Of course, now that I have a DSLR, it is useful).

Should I buy an original manufacturer battery, or is a generic brand OK?

Question

I need another LP-E5 type battery for my Canon 450D. Should I buy an original Canon battery or one of the many generic brands available? There are loads of cheapos on eBay, for example.

I should add that the new battery will be added to my existing Canon battery in a battery grip.

Does anyone have any experience (good or bad) of using generic batteries?

Edit: Thanks for all your advice. On balance I think the general feeling was to buy original brand, so one Canon branded battery ordered from Amazon.

Answer

One of the easiest choices is to buy brand name batteries. From batch to batch the manufacturer takes quality and performance very seriously. You know and I know that in general there will be no lemons. Generic batteries can be made by any number of manufacturers and they all take on the challenge with different perspectives. And as a result if you were to buy from a e-retailer www.dealextreme.com (which has been selling generic batteries from many manufacturers for years) you'll note that customers leave reviews indicating that one generic marque is better than another. One marque will hold almost as much charge as a Canon/Nikon marque for example.

But because generic battery manufacturers often just copy-cat the design and don't really take special care in being faithful to copying everything, they'll miss something that is non obvious. For example there are several cold weather expeditions to Antartica, mountaineering, and ocean faring where photogs discover generic brands to give out all too quickly, rendering the whole trouble of carrying them moot. They all chimed in wishing they had packed genuine brands. So you can imagine a generic battery maker using thin plastic shields without weather sealing because they could shave off a couple of cents and improve profits--not knowing what they are about to do to some of your most important photographic adventures.

Batteries are also intimately connected to the electronics in your camera, you don't want to be in an uneviable situation where Canon or Nikon disclaim their responsibility to repair your camera because they've discovered that the electronics may be busted due to a generic vertical grip, charger, or battery. That could be quite costly.

But do what you must, and do it smartly. For example, you might have some bust up out of warranty camera you bought at a garage sale and you just need to find some el cheapo battery to go with it. So that you can take out the IR screen of the old busted camera's sensor and do some art projects. No harms done and your wallet won't feel all too much lighter.

Should I consider a used Tachihara 4x5" Large-Format camera or an equivalent new alternative?

Question

As my primary photographic interests lie in landscape photography, I've been seriously looking into buying a large-format camera. In my research, I encountered the Tachihara 4x5", which is a beautifully crafted cherry-wood and brass frame camera. Sadly, as I've started looking at prices, it appears it was discontinued...this year! :( sob

I am curious about two things. First, is the Tachihara something worth buying used, and if so, outside of ebay, where might I find a used one? Second, are there any equivalent alternatives to the Tachihara that are still being manufactured? I really loved the cherry wood look of this particular camera, and all of the others I've looked at seemed to be black with simple chrome highlights. If there are comparable wood/brass alternatives to the Tachihara, I would be very interested.

Answer

You can still get the tachihara from mpex.com

What are some good online photo challenges?

Question

A great way to learn and find ideas. Some of these also have mini-games such as post-processing challenges, which is a wonderful way to learn about the different creative ways you can post-process the same image, and what you like best. The smaller and tighter the community, the more likely you will get better and more in-depth critiques.

Reason to be cautious:

  • Beware of scams. (These are typically of the form "Congratulations, your photo has won a prize! We're publishing a very expensive book of the prizewinning photos, would you like to order a copy?". Of course, every entrant has won a prize...)

  • Watch out for the copyright clauses; by entering, you may be assigning all rights in your photo to whoever's running the competition.-

Free:

gizmodo.com/tag/shooting-challenge

dpchallenge.com

dpreview.com

photosig.com

Photo Friday

photocamel.com

photoforum.com

dailyshoot.com

fredmiranda.com

fujimugs.com

pentaxforums.com

dgrin.com

PhotographyBB

About Photography

the mindful eye

Small Aperture

reddit PictureChallenge

streetphotographynowproject

Other sources:

twitter.com/dailyshoot - not a competition, more a daily social game.

Flickr groups

panachallenge.com - targeted mainly to Panasonic users.

Prizes:

Photography Competitions - Photo Contests - Photo Awards

Photo Compete

Answer

Please use answers to rate and comment on each one.

What is bokeh, exactly?

Question

I understand that it refers to out-of-focus areas of an image. But there is obviously more to it than that. How well is bokeh really understood? Is it purely subjective, or can it be evaluated, measured, classified? And how can bokeh be compared and contrasted in different lenses?

Answer

Most importantly: It's not just the disks rendered from a point source, even though that's the simplest way to describe it and see it. The disk is just a shorthand; the lens characteristics that produce these disks are always present; they're what determines the look of the out-of-focus areas in every photo you take!

On the one hand, it's quite well-understood in that cause and effect are fairly well known. On the other hand, what makes one type "good" or "bad" is (as with so many things) extremely subjective and sensitive to context. The general consensus is that good bokeh renders a smooth background without artifacts, but like so many other things, it's possible to make a good picture with "bad" bokeh; it might even be a good picture because of 'bad' bokeh, like the examples with shaped apertures.

Shape: The shape of the disk is determined by the shape of the aperture, and is well-described in other answers (though see also the note on 'distortion' below).

Brightness: The brightness across the disk is influenced by other aspects of the lens, primarily its degree of spherical aberration. There are three basic situations, simulated here: bokeh

In the centre is what you get from a perfectly-corrected lens (or close to it): a disk evenly lit from edge to edge – this is the situation in a large number of modern lenses.

On the left is "smooth" bokeh: a bright centre with a gradual fall-off towards the edge. This is what's generally considered to be desirable, as it blends smoothly and eliminates hard edges in the background.

On the right is what I call "bright-line" bokeh; a bright exterior that fades towards the centre. I'll emphasise that while you get a similar "doughnut" shape from catadioptric lenses, you can see this bright-line effect in many other lenses as well to a lesser degree. Classicaly, this is the less-desirable kind of bokeh, as it will emphasise edges in the background, sometimes to the extent of rendering them as parallel lines.

When you get each type depends largely on spherical aberration, with the background rendering being most important:

  • Under-corrected lenses will typically exhibit smooth bokeh in the background, with the bright-edged type in the foreground. Many of the classic portrait lenses are deliberately designed this way, and it's also what's largely responsible for the very smooth "creamy" look of many older lens designs like the Zeiss Sonnar or Voigtländer Heliar.

  • Over-corrected spherical aberration will produce the opposite; a smoother bokeh in front of the plane of focus, the harsher one behind. This is often a characteristic of lenses that are both fast and sharp, like many 50mm f/1.4 designs, as well as some macro designs (where sharpness is at a priority). While this type of bokeh might be the classically "bad" one, the effect is not usually extreme, and other characteristics of the lens can more than make up for it.

Distortion: Ideally, all disks would be round and a similar shape, but various other aspects of the lens will stretch them to ovals (astigmatism, field curvature), create small tails (coma), or there may even be mechanical obstructions that cut off edges. All of these tend to be much more obvious as you move towards the edge of the frame.

Color: Chromatic aberrations will colour the disk; lateral chromatic aberrations will create the familiar magenta/green fringing, and longitudinal chromatic aberration will cause a slight colour cast over the entire area of the disk, which will be a different colour in front of the plane of focus than behind.

Examples and links:

  • http://www.rickdenney.com/bokeh_test.htm for a very thorough test of a number of different lenses and lens designs. If you want to see an example of classically "good" bokeh, his Sonnar examples are worth checking out.

  • Mike Johnson has an interesting essay about the entry of the term "boken" into English. He also links a list of ratings of various lenses [PDF] (unfortunately with only two examples). To emphasise the subjective and variable nature of things, the same Sonnar design Denney praises gets a 5/10 from Johnson (who I think is using a later Contax SLR version).

Wednesday, July 27, 2011

Whats the difference between Singh-Ray Vari-ND and cheap Fader-ND filters?

Question

I think the Singh-Ray Vari-ND variable ND filter sounds great, but is really expensive.

There are way cheaper variable ND filters from some chinese sites.

I wonder: are the cheap ones worth the money? Is the vari-ND worth the premium you pay for it?

or: what's the difference between cheap knock-offs and the Singh-Ray?

Answer

The mechanism is likely a combination of a linear polarizer and a circular polarizer (which itself is a linear polarizer followed by a quarter wave plate). Thus the differences you can expect between high-quality and cheaper variable ND filters ought to be similar to the differences found among polarizers which include flare, vignetting, inhomogeneity, and color shifts. You can avoid flare in many cases by not including bright lights in the photo; vignetting can be compensated in software and sometimes is desirable; I suspect the inhomogeneities are usually not noticeable; but color shifts can be pronounced. Typically a set of crossed polarizers (which is what you're using to get the heaviest ND settings) pass essentially no colors except violet. Therefore, I would expect cheaper variable ND filters to work OK except at the heaviest settings (more than about 4 stops) where the violet shift will become pronounced.

You can see evidence of vignetting and a violet shift on this dealer's website. Compare the bottom two photos: the one taken with their ND filter has pronounced vignetting (many stops) and a strong blue cast. In contrast, look at the photos on the Singh-Ray site. If you look closely you can see the vignetting, but there's little evidence of a violet shift: look at the grays of the rocks in the stream. Maybe those were post-processed to remove the blue, so the comparison is not definitive, but these two sites nicely illustrate the difference we would expect between good and bad variable ND filters.

I did a quick test using a high-end, top-rated Marumi circular polarizing filter and an old low-end Vivitar linear filter. In combination they made a fine variable ND filter, although there were some color shifts (first to yellow, surprisingly), but below about 3-4 stops a yellow incandescent light started to take a distinctly blue hue. At the maximum density, probably around 6 - 8 stops (I only looked, I didn't measure), only the light was visible and it was a brilliant blue, the color of a Wratten 80b filter.

Your best bet for a cheap solution, then, is actually to look through one of the inexpensive filters and pay special attention to the apparent color at the densest ND settings. While you're at it, look at a bright light through the filter to check for flare and scattering. If everything's acceptable you probably have a great deal.

How does one create the Dave Hill effect for portraits/action shots?

Question

Inspired by the question here by sebastian.b, and the response to the subsequent meta question. I would like to ask how to achieve a specific photo effect.

There may be more photographers that pull this off, but I know of two specific ones. The first is the wonderful photographer, Dave Hill. I know that he does lots of post processing, and his talent goes beyond a short list of tips that I can learn from a website, but I think there is something that I can hope to understand.

What is the Dave Hill effect? I have heard people talk about it, but what is it actually and how does one achieve it?

and

On his webpage, the "Nerd ad", "Allen Robinson", and "Jon Heder" shots give the subjects a specific skin tone/saturation. In general, his portrait shots are amazing. The detail and texture mystifies me. How can I pull this eerie feeling off?

Now the second photographer is skylove from flikr. His shots are also extremely impressive.

Again, he is using some black magic to make skin tone amazing. His subjects look beyond real, and I love it. Three specific examples are energy, discovering, king to defeat. Looking at energy, beyond the absolutely phenomenal idea for the shot and execution, and just focusing on the subject, he has this plaster/grey look, and his skin looks wonderful. Similar things are true for those other shots I linked.

Some ideas I have had that might contribute to this are HDR or possibly just phenomenal lighting setups. I have watched the videos on Dave Hill's website, but they just make me think more-so that he sold his soul to Mephistopheles.

I would appreciate any suggestions on how to achieve these results, or even some direction to go in this direction.

Thanks so much!

Answer

It's all about the lighting!


Most people seem to think it's all done in 'shop but a lot of work goes into the actual setup. Many of the supposed "Dave Hill look" imitations have just used HDR style tonemapping, and the results are nothing like the work of Dave Hill. Compare this:

http://www.flickr.com/search/?q=dave%20hill%20look&w=all

with this:

http://www.davehillphoto.com/

No simlarity at all! Yes there is a lot of post production in Dave's work, but you need to get close with the lighting in order to get the same look. Here is an example, showing what is possible with lighting alone. The first image is straight out of camera:

...the second image is the final image after Photoshop, mostly saturation, contrast and a little high pass filter in an overlay blending layer. I should have pointed out I didn't set out to get the Dave Hill look, I just wanted to play around and see what worked with the subject (the singer in a Ska band). I could have done more in post to get slightly closer to Dave's images.

The key to the look sculpted light. This means large lightsources at oblique angles to the subject. I used two square softboxes right up close and a bare hotshoe strobe for the hair light. Here's how the lights were placed:

The softboxes were brought in really close to maximise the softness of the light, and angled toward the camera to increase the sculpting effect and falloff nicely across the face. Two "gobos" were used to stop flare interfering with the picture (the black lines in the diagram) which is absolutely essential when angling the strobes toward the camera! The hairlight at the back was bare (i.e. no modifier) to really penetrate Aaron's hair and make it glow. As less power is required for an unmodified light I substituted a hotshoe flash for the big monolight.

You can replicate this look on the cheap with a couple of hotshoe flashes but softboxes are important. Something like an umbrellabox is a good option if you're using small battery flashes. You just don't get the same effect with umbrellas as they spill too much light out the sides, and are in general harder to fine tune as you don't get a crisp edge to the light. The curved profile of the umbrella also makes it hard to get close. Getting close basically makes your softboxes bigger. Dave would have used huge octoboxes further away to give the model more space but he gets paid more than I do ;)

edit you can actually see Dave's setups in his behind the scenes videos (which I've just noticed you mentioned in your question!). And yup there's some big octoboxes! http://www.davehillphoto.com/bts/

Here's another example of the same look in a group shot I did for the band Asking Alexandria. This one required a bit more post production (as lighting groups is much harder) so I'll take it step by step to show you what sort of post production you can do to push the look to it's limits.

As before lighting is still very important. I used a very similar setup to the previous example but with the softboxes much more symmetrical. The models stood in a triangle pattern so the light hits everybody. The hairlight is also much higher this time as we're lighting the top of the head, not shining through anyone's hair (which would have required three hairlights in this example). You can see the lightstand for the hair light in the straight out of camera shot, behind the guy on the left.

Here's the image after Raw conversion in Adobe Camera Raw, where I added a little of the clarity slider, brought up the black point and used a lot of the fill light slider. I wasn't going for any specific look, just to get an image with detail and a good tonal range to work with. The background clutter has been removed by a manual selection. Also note I've made the image taller by adding more black. I planned to do this so I shot the original very tightly cropped to make the most of my megapixels (I didn't do this with Aaron as some of the shots we took involved a lot of movement).

Here I've faded a little of the ground into the image with a gradient mask in order to ground the models and make them look a little less like they're floating in space!

Next I went mental with the Photomatix tonemapping plug-in! With any sort of HDR work taste and subtlety is important. I find the easiest way to achieve this is to push it as far as I can and then fade it into the original at a very low opacity to retain some realism.

Here it is reduced in opacity to 30%. I actually lowered it to 15% in the final version, I just wanted to show the effect in bringing out the details in the legs and shoes that was lost due to the fact I concentrated on lighting the faces (and didn't have any striplights to hand). It's also done a nice job with the hair.

Now here's pièce de résistance of the post processing. I've duplicated the original applied a high pass filter (which removes small details such as noise) and leaves large scale tone changes. The layer is blended back in at 30% with the blending mode set to overlay, this is very important as it sort of amplifies the high pass by lightening the lights and darkening the darks. It's starting to look how I want it now.

Here's the final image after some fiddling dodging and burning here and there, some minor colour correction (I moved the jeans away from cyan and desaturated for a more pleasing look). Desaturated skin tones makes this lighting technique look better in almost all cases. Finally the image is resized and sharpening applied, leaving an image which I think captures the look you are going for based on the examples posted.

It's worth noting that you need a dark place in order to pull this off otherwise you lose control over the light and you will have difficulties getting the deep shadows required for maximum contrast. The first image of Aaron was shot in a black walled studio, but if you don't have access to a studio you can get the same effect in any large space. The size is important as the light that gets reflected back from other objects falls off with the squre of the distance (double the space, 4x less light bouncing off walls), up to the point where it is totally overpowered by the subject and you get a nice black background. If you're looking for a large space, the great outdoors comes in very handy!

Does the Nikkor 50mm f/1.4g perform better than the f/1.8d?

Question

Looking into these two lenses, I'm getting the impression that for my Nikon D-90 with DX camera sensor that the f/1.8d would waste light that is cropped by the sensor whereas the f/1.4g would not as it is designed for the DX style. Further, the f/1.8d is not available as AF-S whereas the f/1.4g is AF-S.

Is my analysis correct and thus the f/1.4g will perform better with the DX style camera?

Answer

The Nikon AF-S 50mm f1.4 G is not designed for the smaller DX sensor and has the same image circle as the 1.8

Are you thinking of the AF-S 35mm f/1.8 G DX which is designed for a smaller sensor compared to the AF-S 35mm f/1.4G?

In any case the size of the image circle is of minor importance to the light gathering ability - only the aperture matters, as Evan states.

Despite a lens designed for a smaller image circle letting in less light total, it lets in the same light per unit area, so if you swap one lens for another designed for a larger image circle, but the same f-stop then your exposure would be the same.

The previous paragraph ignores vignetting, or the tendency for brightness to fall off across the frame. This usually gives lenses designed for a larger image circle a brightness advantage. There are other advantages to using lenses designed for the sensor you are using, such as sharpness, weight and better resistance to flare.

Where does Lightroom keep the original raw file?

Question

Yesterday I realized that for the last import I did with Lightroom I don't have the original RAW files from the camera's SD. In the memory card I have only the RAW file and when I import them in Lightroom it converts in JPEG and save them to the library.

There are any particularly options for keeping the original RAW during the import?

update Sorry....I'm a fool! Someone changes my settings and I didn't realize that I was shooting in jpeg. I double checked and yes, it's only JPG!:( sorry for the wasting of time

Answer

Lightroom always keeps the RAW file. It does not convert on import, it converts on Export. Your files will be in your designated LR import folder. Note that there can be more than one of these if you like.

So to find out where your last photos went, you can simply open Lightroom and click "Import". One of the gotcha's of Lightroom is that it imports wherever you last told it to. So simply click on 'Import' and see where it is going to put the files. This will be the place it put them last time. In LR3, this is the top right hand of the UI, where is says "to".

Does the Nikkor 50mm f/1.8d perform better than the f/1.4g?

Question

Looking into these two lenses, I'm getting the impression that for my Nikon D-90 with DX camera sensor that the f/1.8d would waste light that is cropped by the sensor whereas the f/1.4g would not as it is designed for the DX style. Further, the f/1.8d is not available as AF-S whereas the f/1.4g is AF-S.

Is my analysis correct and thus the f/1.4g will perform better with the DX style camera?

Answer

The Nikon AF-S 50mm f1.4 G is not designed for the smaller DX sensor and has the same image circle as the 1.8

Are you thinking of the AF-S 35mm f/1.8 G DX which is designed for a smaller sensor compared to the AF-S 35mm f/1.4G?

In any case the size of the image circle is of minor importance to the light gathering ability - only the aperture matters, as Evan states.

Despite a lens designed for a smaller image circle letting in less light total, it lets in the same light per unit area, so if you swap one lens for another designed for a larger image circle, but the same f-stop then your exposure would be the same.

The previous paragraph ignores vignetting, or the tendency for brightness to fall off across the frame. This usually gives lenses designed for a larger image circle a brightness advantage. There are other advantages to using lenses designed for the sensor you are using, such as sharpness, weight and better resistance to flare.

Does the 'Other Dynamics' brush option exist in Photoshop CS5?

Question

I have CS3 on one computer and CS 5 on another. On CS3 my dynamic brush options have a section called 'Other Dynamics' that allows me to change jitter opacity, but my CS5 does not have that option in the same area.

Does CS5 not have 'Other Dynamics' for brushes or is it just somewhere else?

Thanks

Answer

Go to the Brush panel (Window -> Brush, or F5), select the "Brush" tab. You will find "Opacity Jitter" in the "Transfer" section.

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Why do the differences between APS-C and full frame sensors matter?

Question

I'm trying to decide on a model in the Canon DSLR range, and I guess it's a choice between the 7D and the 5D MkII.

I understand that the sensors are of different sizes, and as such have an effect on the perceived magnification of the lens, with the smaller APS-C sensor having an effective focal length greater than what it otherwise would be with a full frame sensor. But why does this matter?

  • What things should drive my choice between one or the other?
  • In which situations is one better than the other, and why?

Answer

  • One major difference is that a FF camera produces a depth of field that's around 1.3 stops shallower than an APS-C camera for the same subject & framing. This is most important when you have the aperture as wide as possible, e.g. for portraiture. To replicate the look of a 50 f/1.4 lens you'd have to use something like a 31 f/0.9 lens, which doesn't as far as I know exist!

Quick and dirty comparison image, APS-C Canon 30D left, FF Canon 5D right, same lens, same composition, both f/2.8

  • Another difference is that if you're using a lens designed for a full frame camera (like all Canon EF lenses) you are making full use of the image circle, which is less demanding of the optics and so you can expect a sharper image for the same number of megapixels. It's true that some lenses get softer toward the edge of the image, but you will still get higher average sharpness with most lenses, and telephotos will be sharper right across the frame. The crop factor of APS-C cameras takes the middle out of the lens and blows it up, losing sharpness in the process in a similar manner to a teleconverter. See this related question:

  • With all other things equal, in a DSLR, will a larger sensor produce a sharper image?

  • A bigger sensor means bigger pixels, which in turn means you capture more light usually achieving lower noise levels in the process. Greater dynamic range goes hand in hand with this.

  • You get a larger, brighter viewfinder on a full frame camera, which can be helpful composing shots. Having said that, I personally find the 5D viewfinder too large, I've not used a 7D but it has a very high spec 'finder.

  • You have more mirror to move on a full frame camera. The larger heavier mirror usually means shooting speed is limited. The mirror on my 5D moves so slowly I can actually see the world slide sideways/up for an instant!

  • Likewise the mirror box, focussing screen and pentaprism are larger, meaning the camera is larger and heavier.

  • Lens hoods are designed for FF image circle and are therefore slightly more effective on FF cameras. This mostly applies to prime lenses, as zoom lens hoods are designed cut to accommodate the widest zoom setting, so everything else is already non optimal. If you're using an EF lens on a crop camera you ideally want the hood tighter (since the extra shading will lie outside the smaller sensor a tighter hood wont vignette.

I have nothing against APS-C cameras but for any format it makes sense to use lenses designed for your sensor size. The range of EF-s lenses is smaller than the range of EF lenses. However for some uses (sports etc.) the smaller sensor size is helpful for the extra reach and speed it allows. Also the better noise characteristics of a FF sensor don't quite make up for the higher ISO you need to use get the same exposure when stopping down to match the DOF as a crop. So if you have to maximise DOF crop has a slight edge.

If there are EF-s lenses available for what you want to shoot then it wont be noticeably worse choosing this camera. However I feel full frame gives you more flexibility (speed aside) - as you can get the same deep DOF as a crop, but go narrower if you need to.

Which camera has the best features for still photography: Canon 60D, 50D or 7D?

Question

Now that the 60D specs are released.

When choosing a camera for still photography (no movies) which one of Canon 50D, 60D and 7D has an edge over the others and why?

What still photography features does each camera, respectively, have that the others don't?

Answer

There is a very good feature comparison on dpReview site

To give you some summary:

In terms of picture quality I would say that you would not spot a difference between results achieved from all the camera on the list, and I would say that the choice would be more related to handling and the way you are planning to use the camera.

7D is pro grade body, with magnesium body and environmental sealing. It has an excellent pro grade autofocus and offers 100% view viewfinder. So it will have an edge when it come to shooting sports, birds and in rough conditions. Those features come at price though.

50D has pretty similar body to 7D (magnesium) but it is not that well sealed and the autofocus is a bit lower quality as well.

60D has plastic body, same autofocus as 50D and similar sensor to 7D. It offers swivel LCD which can come handy in some situation, and its lower weight and size can be considered an advantage by some (me included).

So you need to handle the cameras, consider your budget a see which one works best for you.

What are the differences between Picasa and Lightroom, other than price?

Question

I've heard about Adobe Lightroom before, but never really understood what's so great about it, or why you'd pay for it when you can get Picasa for free.

I know Lightroom probably has more sophisticated editing options, but what are they, exactly, and how to do they compare to Picasa? Why would you use one over the other? Is Lightroom better for streamlining editing workflow, but Picasa is better for organizing & tagging photos? And would you ever use both programs?

Basically, what are the differences between Picasa and Lightroom?

Answer

There are several features that I think are just awesome in one or the other. Depending on your needs, one of these features will make you (usually + some other things) go towards Picasa or Lightroom.

Lightroom:

  • Integration with other Adobe product (Photoshop, InDesign, etc)
  • More sophistication in editing (somewhere in between Picasa & Photoshop)
    • Color correction, CA correction
    • NR & sharpening
    • Exposure & WB adjustments
  • Can do batch processing

Picasa:

  • Arguably faster (much faster for me)
  • Integration with Google product (Blogger, etc)
  • Simpler editing tools

So, if your workflow deals with more Photoshop, other Adobe stuff, Lightroom is the way to go. If you need more editing tools but don't want Photoshop, go Lightroom. Other than that, like me, I went for Picasa.

What film rangefinder camera can I buy for a reasonable price?

Question

I'm interested in trying out film photography and I would also love to try out a rangefinder camera as those seem to be perfect for manual focusing in street photography.

Now, of course, the question is: Which camera and lenses should I buy? What are the differences? I'm all new to these cameras, so don't hesitate to include some very basic stuff in your answers :)

Regarding the price: As it is an experiment, I don't want to spend any more than 1000 USD in total for the beginning. If the whole thing turns out to be not for me, I should be able to sell the equipment for a good price, right?

Answer

If you're willing to reduce your budget by a factor of 10, you could get a Canonet QL17 GIII, which has a permanently mounted 40mm f/1.7 lens and shutter-priority auto exposure. I really enjoyed mine and considered it an excellent value. The 40mm focal length suited me well, and the lens "drew" nicely, with sharp focus and pleasant bokeh.

Tour guide, Ste.-Chapelle (Paris)

Hale Telescope, Palomar Observatory

What, exactly, is bokeh?

Question

I understand that it refers to out-of-focus areas of an image. But there is obviously more to it than that. How well is bokeh really understood? Is it purely subjective, or can it be evaluated, measured, classified? And how can bokeh be compared and contrasted in different lenses?

Answer

Most importantly: It's not just the disks rendered from a point source, even though that's the simplest way to describe it and see it. The disk is just a shorthand; the lens characteristics that produce these disks are always present; they're what determines the look of the out-of-focus areas in every photo you take!

On the one hand, it's quite well-understood in that cause and effect are fairly well known. On the other hand, what makes one type "good" or "bad" is (as with so many things) extremely subjective and sensitive to context. The general consensus is that good bokeh renders a smooth background without artifacts, but like so many other things, it's possible to make a good picture with "bad" bokeh; it might even be a good picture because of 'bad' bokeh, like the examples with shaped apertures.

Shape: The shape of the disk is determined by the shape of the aperture, and is well-described in other answers (though see also the note on 'distortion' below).

Brightness: The brightness across the disk is influenced by other aspects of the lens, primarily its degree of spherical aberration. There are three basic situations, simulated here: bokeh

In the centre is what you get from a perfectly-corrected lens (or close to it): a disk evenly lit from edge to edge – this is the situation in a large number of modern lenses.

On the left is "smooth" bokeh: a bright centre with a gradual fall-off towards the edge. This is what's generally considered to be desirable, as it blends smoothly and eliminates hard edges in the background.

On the right is what I call "bright-line" bokeh; a bright exterior that fades towards the centre. I'll emphasise that while you get a similar "doughnut" shape from catadioptric lenses, you can see this bright-line effect in many other lenses as well to a lesser degree. Classicaly, this is the less-desirable kind of bokeh, as it will emphasise edges in the background, sometimes to the extent of rendering them as parallel lines.

When you get each type depends largely on spherical aberration, with the background rendering being most important:

  • Under-corrected lenses will typically exhibit smooth bokeh in the background, with the bright-edged type in the foreground. Many of the classic portrait lenses are deliberately designed this way, and it's also what's largely responsible for the very smooth "creamy" look of many older lens designs like the Zeiss Sonnar or Voigtländer Heliar.

  • Over-corrected spherical aberration will produce the opposite; a smoother bokeh in front of the plane of focus, the harsher one behind. This is often a characteristic of lenses that are both fast and sharp, like many 50mm f/1.4 designs, as well as some macro designs (where sharpness is at a priority). While this type of bokeh might be the classically "bad" one, the effect is not usually extreme, and other characteristics of the lens can more than make up for it.

Distortion: Ideally, all disks would be round and a similar shape, but various other aspects of the lens will stretch them to ovals (astigmatism, field curvature), create small tails (coma), or there may even be mechanical obstructions that cut off edges. All of these tend to be much more obvious as you move towards the edge of the frame.

Color: Chromatic aberrations will colour the disk; lateral chromatic aberrations will create the familiar magenta/green fringing, and longitudinal chromatic aberration will cause a slight colour cast over the entire area of the disk, which will be a different colour in front of the plane of focus than behind.

Examples and links:

  • http://www.rickdenney.com/bokeh_test.htm for a very thorough test of a number of different lenses and lens designs. If you want to see an example of classically "good" bokeh, his Sonnar examples are worth checking out.

  • Mike Johnson has an interesting essay about the entry of the term "boken" into English. He also links a list of ratings of various lenses [PDF] (unfortunately with only two examples). To emphasise the subjective and variable nature of things, the same Sonnar design Denney praises gets a 5/10 from Johnson (who I think is using a later Contax SLR version).