How can I avoid a strange lens flare at bright lights when using UV filter?

Question

I have a Panasonic Lumix GF1 with the kit 20mm f/1.7 lens. I put a UV filter on it (this one: http://www.amazon.com/gp/product/B00004ZCJE/ref=oss_product), simply as protection for the glass. I'm doing lots of theatrical shooting (bright lights, etc.) and I'm getting lots of lens flare in my shots. Here's an example: http://www.flickr.com/photos/schof/5006914162/

If I remove the filter, the flare goes away. Since I'm just using the filter to keep the lens glass clean and protected, is there another type of filter I should be using (or another brand of UV filter) to avoid this lens flare?

Asked by Schof

Answer

Thats actually a UV filter not an ND filter, very different filters :) Anyway, lower quality filters flare more, if you want to continue to use a UV filter consider a multi-coated filter. It seems other people who bought that same filter had similar complaints, see the 1st review:

"However, I had to return this item since they DON'T contain any anti-glare/reflective coating on them"

Se a similar post here re: UV filters:

Where to buy cheap UV filters online?

My advice though would be to just not use a filter, shooting directly at light sources like that is going to cause enough problems as is with flaring.

Answered by Shizam

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How do non-MFT lenses work on a Panasonic GF3?

Question

I'm thinking of buying a GF3. But the lenses are pricy, so I have to pick my kit wisely. I saw that there are adapters for it, but I'm new to lenses.

• Are there any problems with attaching non-MFT lenses?
• How can I see the image from the lens without a viewfinder? (Is it going to show correctly on the display?)
• Can external lenses be used with Raynox DCR 250?

Answer

You can mount pretty much anything on a m43 system using the right mechanical adapters, but that doesn't mean ergonomics are going to make it a practical option, specially on a camera with limited controls like the GF3.

You view through the viewfinder as with any m43 lens, but will be working in aperture priority mode. You can trigger manual focus assist, which will show you a magnified view of the focus area, but you will have to trigger it manually (unlike manual-focus m43 lenses like some Voigtlander models, where turning the focus ring automatically triggers MF assist).

In practice, using non-m43 lenses on a m43 body is not ideal. It's perfectly OK for landscapes, still lifes and street photography using estimated scale focus, but not anything involving action.

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Should I get the prime or zoom kit lens with the Panasonic GF3?

Question

I'm new to lenses, because currently I have the fixed lens Olympus XZ-1. I'm thinking of an upgrade, and I find the Panasonic GF3 very good. It has the option of two kit lenses: A pancake lens at 14mm f/2.5, or the 14-42mm f/3.5-5.6.

I saw that the bigger (14-42mm) lens has a 3x zoom, which isn't anything special and the 14mm has F2.5 in comparison to F3.5 of the 12-42mm lens. Which should I choose? Are those the only differences, -1.0 of F and 3x zoom? The 14-42mm is way bigger, and if that's the only difference maybe I'll stick with the smaller 14mm lens.

Also I am thinking of getting Raynox DCR250 to take macro shots.

My main questions are:

• Is the only difference the zoom and the maximum f-stop?
• Which one is better to use with the Raynox to make macros?
• Which one is better for landscape photography?

Answer

I will present the "quick and dirty" version of my answer, because I could talk on this topic for pages and pages. Essentially the 14mm f/2.5 "pancake" is a prime lens, which means it does not zoom, it has one fixed focal length. So instead of zooming in and out to frame your subject, you have to move your feet along with the camera! The fixed focal length usually comes with a few advantages such as:

• Large apertures that zoom lenses do not have
• Very high quality optics due to easier manufacturing of the single focal length
• Size can be a huge advantage, and only primes can really get the "pancake" form factor

The other option you are looking at is a general purpose zoom lens. The 14-42mm is equivalent to 28-84mm angle of view in the 35mm format, which is handy to know when comparing it to something like your old Olympus XZ-1 6-24mm, which had a 28-112mm 35mm equivalent angle of view. So the easiest way for you to compare the lenses on the two cameras you are considering is probably the following when considering the field of view:

• 14mm "pancake" = 28mm field of view
• 14-42mm = 28-84mm field of view
• 6-24mm = 28-112mm

Someone else will likely chime in and explain how I forgot a few important details when explaining focal length conversions and field of view, but this is the simplest way I can explain it to you that I hope will make sense to a beginner. What is important to understand, is the "field of view", in that, the pancake lens will look just like your current Olympus zoomed all the way out. And the 14-42mm standard zoom will look almost like the Olympus - but will not let you zoom in quite as far.

Other things to consider as you suggested, is the maximum aperture. This is how much light the lens will let into the camera, and is very important. The larger the better. f/2.5 is the maximum the pancake lens will allow, and f/3.5 is the maximum the standard zoom will allow. Your old camera had a maximum of f/1.8 which is larger then both of these Panasonic lenses. Both zoom lenses have variable maximum apertures, so as you zoom in the maximum aperture becomes smaller, which is not a great thing. The prime "pancake" lens has only one maximum aperture since it does not zoom, which is a good thing.

I hope this helps shed a bit of light on what to purchase. In the end the choice between a prime lens and a standard zoom is really up to you, the user. I would say that the majority of people end up with a standard zoom at first, and as a second lens they may choose a prime, but this may not be the correct choice for everyone.

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Which kit lens to get with the Panasonic GF3?

Question

I'm new to lenses, because currently I have the fixed lens Olympus XZ-1. I'm thinking of an upgrade, and I find the Panasonic GF3 very good. It has the option of two kit lenses: A pancake lens at 14mm f/2.5, or the 14-42mm f/3.5-5.6.

I saw that the bigger (14-42mm) lens has a 3x zoom, which isn't anything special and the 14mm has F2.5 in comparison to F3.5 of the 12-42mm lens. Which should I choose? Are those the only differences, -1.0 of F and 3x zoom? The 14-42mm is way bigger, and if that's the only difference maybe I'll stick with the smaller 14mm lens.

Also I am thinking of getting Raynox DCR250 to take macro shots.

My main questions are:

• Is the only difference the zoom and the F?
• Which one is better to use with the Raynox to make macros?
• Which one is better for landscape photography?

Answer

I will present the "quick and dirty" version of my answer, because I could talk on this topic for pages and pages. Essentially the 14mm f/2.5 "pancake" is a prime lens, which means it does not zoom, it has one fixed focal length. So instead of zooming in and out to frame your subject, you have to move your feet along with the camera! The fixed focal length usually comes with a few advantages such as:

• Large apertures that zoom lenses do not have
• Very high quality optics due to easier manufacturing of the single focal length
• Size can be a huge advantage, and only primes can really get the "pancake" form factor

The other option you are looking at is a general purpose zoom lens. The 14-42mm is equivalent to 28-84mm angle of view in the 35mm format, which is handy to know when comparing it to something like your old Olympus XZ-1 6-24mm, which had a 28-112mm 35mm equivalent angle of view. So the easiest way for you to compare the lenses on the two cameras you are considering is probably the following when considering the field of view:

• 14mm "pancake" = 28mm field of view
• 14-42mm = 28-84mm field of view
• 6-24mm = 28-112mm

Someone else will likely chime in and explain how I forgot a few important details when explaining focal length conversions and field of view, but this is the simplest way I can explain it to you that I hope will make sense to a beginner. What is important to understand, is the "field of view", in that, the pancake lens will look just like your current Olympus zoomed all the way out. And the 14-42mm standard zoom will look almost like the Olympus - but will not let you zoom in quite as far.

Other things to consider as you suggested, is the maximum aperture. This is how much light the lens will let into the camera, and is very important. The larger the better. f/2.5 is the maximum the pancake lens will allow, and f/3.5 is the maximum the standard zoom will allow. Your old camera had a maximum of f/1.8 which is larger then both of these Panasonic lenses. Both zoom lenses have variable maximum apertures, so as you zoom in the maximum aperture becomes smaller, which is not a great thing. The prime "pancake" lens has only one maximum aperture since it does not zoom, which is a good thing.

I hope this helps shed a bit of light on what to purchase. In the end the choice between a prime lens and a standard zoom is really up to you, the user. I would say that the majority of people end up with a standard zoom at first, and as a second lens they may choose a prime, but this may not be the correct choice for everyone.

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What is the best setup for shooting sports at night with a point & shoot camera?

Question

I always try to take good photographs in soccer matches or in races at night, not using flash, and I have always the same result: too much blurred photos.

I don't have an SLR, but I'm sure that's not the problem; the problem is the setup.

What I have to do?

My camera is a Panasonic Lumix FZ18.

Thanks!

Answer

Actually, shooting with a compact camera rather than an SLR is part of the problem. Basically, shooting a game at night means that you don't have enough light for decent exposure times. As a consequence, your exposures are long and the moving objects are burred. The field's lighting are rarely enough to allow you to capture moving subjects with ISO low enough so noise is not a problem. In this case, the options are to:

1. Add lighting (e.g., use a flash - but in your specific case there are 2 problems: your camera does not support an external hot-shoe flash, which may be solved by an optical slave, and more seriously, typical compact flashes just don't have enough power to light a soccer field effectively but it may be just fine for a race track if you can get close to the action).

2. Use a lens with large maximum aperture (small F-number). Your camera offers F2.8 which is not bad for this purpose, but in the SLR world you have lenses with bigger apertures.

3. Use a camera with more sensitive sensor. P&S cameras typically have far smaller sensors compared to SLR's. In the digital world, the bigger the sensor - the better its light recording ability. Pro sports shooters use full-frame, or at least APS-C bodies for the advantage in high-ISO low noise images they have over P&S cameras. You can dial up the ISO in your camera but the images will become very noisy/grainy vary fast. Also note that your camera is pretty old (2007 model?) which means that even for this form factor, you can expect better ISO performance from newer technology.

So, as you see, SLR camera will certainly help you to achieve better images in these tough conditions.

On top of all - remember to always use a tripod there and a remote release if possible. Even if the players and the ball end up somewhat blurred, at least the field and the background will remain sharp.

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How can I remote control my Panasonic FZ100?

Question

I want to remote control my Panasonic DMC-FZ100 from my computer via USB. It does support PTP but gPhoto2 says Error (-6: 'Unsupported operation'). libptp also returns an error.

Do you know any other software to take still images with the FZ100?

Linux preferred but I have Windows in a VM, too.

Answer

As I understand it, that camera does not offer that feature via any software. I did a little looking on gphoto2 forums, and in general it seems Panasonic's support for the PTP protocol used for USB communication is very rudimentary, on pretty much all of their compact camera models. So, basically: sorry, can't really be done.

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Why does viewfinder spec state 3 times more dots than there are pixels?

Question

My DMC-G2 has a viewfinder spec of 1,440,000 dots, but I read a review that says it is really 480,000 pixels:

The electronic viewfinder has an extremely high resolution of 1,440,000 dots (480,000 pixels), offering a 100% field of view and 1.4x magnification. The Panasonic G2's viewfinder has a generous +/-4.0 diopter adjustment range, and a rather tight 17.5mm eye point.

What gives? How am I supposed to compare with other cameras?

Answer

I'm a bit skeptical about what they are stating. It says that the viewfinder is "1,440,000 dots equiv". The "equiv" term is an annoying marketing term used when trying to be competitive without stating the true nature of something, they are simply stating it is "equivalent to" such a thing. The Electronic Viewfinder is "equivalent" to a "1,440,000 dot" resolution. Whatever that means, who knows, but I doubt its actually truly 1.4 million dots.

EDIT: Based on the linked review, the EV has 480,000 "pixels" comprised of 1,440,000 "dots". This is a wacky marketing way of saying that it has 480,000 dots each of red, green, and blue, the triplets of which make up a resolution of 480,000 total pixels in a 4:3 form factor. This boils down to a EV screen size of around 1470x1100 pixes.

Comparing the viewfinder with other DSLR's. This viewfinder is 100% coverage and 1.4x magnification. The magnification is multiplied by the sensor size, which is 17.3x13.0mm. Thats a viewfinder size of 24.22x18.2mm, which is basically APS-C size. In contrast, a Canon or Nikon APS-C DSLR will usually have 95-97% coverage and anywhere between 0.70x to 1.0x magnification, depending on the model. Most of the entry-level DSLR's are around 0.85-0.95x, while the Canon 7D is a 100% 1.0x APS-C viewfinder. A Canon 5D Mark II is a 98% 0.71x viewfinder, which is again about the size of an APS-C sensor.

The LCD screen on the back has "460K dots" in it, which these days is pretty low. Most of the more recent Canon and Nikon LCD screens have 920k or 1040k dots.

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Why is the pixel count of RAW images from the Panasonic LX5 slightly larger than the generated JPEGs?

Question

I'm new to working with RAW images, and I'm capturing simultaneous RAW+JPGs with my new Lumix LX5, and using Bibble to view/process the results.

I'm very surprised that the RAW images taken at 24mm wide 16x9 seem to capture a different (and larger) sensor area compared to the JPGs. The RAW images seem to contain the equivalent of about 100 extra pixels on left and right sides, and a smaller number top and bottom. I say "equivalent", because the actual pixel counts of RAW and JPG are only slightly different, which implies some resizing must be going on...?

JPG: 3968 x 2232 RAW: 3976 x 2238

I guess this small difference is because JPG images must be 16x16 multiples>

The raw image displays noticeable vignetting in the extra pixels, and there's a fair bit of chromatic aberration. I can crop off the 'extra' pixels, but then my RAW image has fewer pixels in it than the JPG, which doesn't feel right.

I'll try and add samples shortly.

Answer

Firstly there are a couple of general reasons raw and JPEG images differ in size, and raw differs from the actual number of pixels on the sensor:

Whilst JPEG image dimensions don't have to be multiples of 16 (or 8 if not using chroma subsampling) it is more efficient to do so, as it allows you to rotate the images without re-encoding (lossless rotation). So that can account for a small image size difference, as you say.

Even raw image sizes typically differ from the actual number of pixels as most sensors have strips masked pixels (that receive no light) down each side in order to detect banding issues with uneven amplification. Further, the size you see in your raw viewer will differ from the actual raw data as some image processing operations use a form of averaging which doesn't work at extreme edges (because there's no data beyond the image to use when averaging) so they get cropped off when the image is viewed/converted.

Secondly the Panasonic Lumix LX3 and LX5 have a different sensor design to most cameras, which is partially responsible for the difference in coverage between raw and jpeg you are experiencing:

The maximum 16:9 image size is actually wider than the maximum 4:3 image size. You would expect them to be the same width but different heights.

This is because they've made the sensor a bit wider for 16:9, employing a non rectangular design and it's pushing the very edges of the lens image circle, this explains the vignetting and CA you observe with the raw. This diagram shows the irregular design:

As John Cavan suggests, the JPEG image pipeline is doing some correction, including barrel distortion correction, given that 24mm equiv. is very wide for a compact, and the sensor is pushing to the very edge of the image circle.

Barrel distortion correction makes straight lines straight again, but will cause the image edges to bend in response. In response to this the correcting transformation enlarges the image slightly and crops to get straight edges again.

Can you see any differences in the appearance of straight lines between the raw and JPEG? It might be quite subtle but get revealed if you overlay them.

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