Why do compact digital cameras not have the aperture range of DSLRs?

Question

Why is it that on compact digital cameras the aperture never seems to go any smaller than about F8 ? Even on high-end compacts such as the Cannon G10 or Panasonic LX5. Is there some practical or physical limitation due to the size of the camera or the CCD which prevents this from being possible?

Asked by mdresser

Answer

Although the relative aperture numbers — the ƒ stops — are the same regardless of format, the actual focal lengths of the lenses on small cameras are quite low: 5mm or 6mm at the wide end. That in turn means that the real aperture is small, which is why the diffraction limit kicks in sooner.

The smaller format also means that depth of field is hugely increased — even wide open at f/2.8, a camera like the Canon G10 has an infinite depth of field if you're focusing farther away than a few feet. So, there's not much difference in that aspect of changing aperture, so from that point of view there's no point even bothering. And that's presumably why there's usually not many choices besides wide open and one closed-down stop like f/8. (Because everything is small, and competitive price pressure significant, adding the mechanics for more intermediate stops is easily deemed not worth it.)

The other aspect of a smaller aperture is, of course, controlling exposure in bright light, without artificially dropping ISO beyond the sensor base or using very high shutter speeds. Some compact cameras actually use a dark neutral-density filter instead of closing down the aperture, specifically to avoid issues with diffraction.

Answered by mattdm

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Why are my photos taken at f/11 less sharp than those taken at a wider aperture?

Question

I am new to photography. I have Fujifilm FinePix HS10 camera. Lately I was trying my hands on landscape photography.

I learnt from different tutorials that setting high aperture value gets most of the scene in focus. Hence proceeding with this notion I set my aperture value to f-11 which is the highest on my camera.

But what I observed is that, f-11 images were very soft and I don't see that background elements well focused.

On the contrary, images taken in range f-4 to f-5.6 were better looking in terms of sharpness of background elements. I have attached sample images for your reference.

Can you please shed some light on this?

Image taken with f-4

Image taken with f-11

Asked by Vaman Kulkarni

Answer

Images with your camera will start showing signs of diffraction around f/4 to f/5.6 due to the size of the sensor. Shooting at a significantly smaller aperture (like f/11) will only increase the diffraction problems. You'll lose resolution.

Here's a good tutorial on diffraction:

http://www.cambridgeincolour.com/tutorials/diffraction-photography.htm

Answered by Eric

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Do compact and DSLR cameras have the same sensor size if they have the same number of megapixels?

Question

In the analog camera, I understood the impact of using a 35mm film vs using a 70 mm film.

However in digital world, I dont know if the sensor size is the same for compact and DSLRs. In other words, if I use a compact and DSLR both of 12 megapixels and, say, with a lens of 35mm, will there be any difference in terms of resolution of the image?

Asked by Dheer

Answer

Sensor area doesn't determine resolution in the same way as the film era. Back then simply increasing the area of film would yield a similar increase in the size you could print, and therefore the detail you captured. In the digital world sensors can have different numbers of pixels per cm

Both 12MP compact and DSLR will resolve similar levels of detail but the DSLR sensor will be about 5-6 times bigger in each dimension. The extra size tends to provide better low light abilities as well as shallower depth of field at the same f-stop. This is because at the same f-stop a small and large sensors receive the same light per unit area, however a larger sensor receives more light in total leading to a reduction in photon noise. The difference in depth of field is due to the need to use a longer focal length for the same field of view, giving a larger apparent aperture.

Important note:

Differences in light gathering ability, DOF are not absolute and depend on the actual lenses that are available. For example it is true that for a small sensor compact and DSLR with f/2.0 lenses the DSLR will gather more light and have shallower DOF, however if you compare a 35mm DSLR to a medium format camera (with larger sensor) you might find that f/2.0 lenses aren't available for the medium format, so the smaller sensor 35mm DSLR can gather more light and attain shallower depth of field due to the availability of fast lenses.

Second note:

Not all compacts have small sensors, some now have sensors the same size as most DSLRs, such as the Fuji x100, Sigma DP1, the new Canon G1X and the Sony NEX range, and some are in between - e.g. the micro 43rds and the Nikon 1 series.

Answered by Matt Grum

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What is a Carl Zeiss lens in a camera?

Question

I have a Sony CyberShot camera and I don't know why they use a lens in the camera. What is a Carl Zeiss lens?

Answer

A lens is needed to focus light on imaging sensor. For example, here's an image taken without lens attached to camera:

For comparison, same scene taken with a lens attached:

Carl Zeiss is a German manufacturer well known for carefully designed good quality optics; see also what makes a Carl Zeiss lens so special in a smartphone (the reasons are similar for a pocket camera).

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What is the cause of these round spots on my photograph?

Question

Is this a finger print on the lens? I don't know.
What can be the cause of the round spot on this photograph?
I have many times cleaned the lens with my fingers, never saw anything like this before.

Canon PowerShot SX210 IS

Answer

Spots like this are due to something on or very, very near the sensor. See Dust-like speck visible every few pictures — is it dust, or worse? for another example. Dust in or on the lens can't cause this problem, because, like lens scratches, they'll be so far out of focus that the effect is undetectable (in the same way a window screen becomes invisible when focused far away through it).

On an SLR, you can access the glass protecting the sensor, and it's not much of a worry, since you can clean this. And automatic cleaning technology has gotten better. With my first couple of DSLRs, this was a constant annoyance. The first one had no real self-cleaning mechanism, and the second did, but it was ineffectual. With my current camera, which I got in 2009, I've never once had a problem with dust, and I change my lenses a whole lot more than I did five years ago.

With a compact camera, though, the whole thing will need to be disassembled, and this isn't something you can easily do at home — they're not made to be user serviceable. A camera service center will be able to do it, and if they're feeling charitable may in fact clean the sensor under warranty for free. Out of warranty, or if they decide the dust is due to environmental conditions you should have been more careful about, it's generally unreasonably expensive. (I once paid $100 to have a Fujifilm F31fd cleaned in this way.)

So, in this lovely world of disposable consumer gadgets, most people consider this time to get a new camera. If you get a new camera which doesn't have either built-in sensor cleaning or a way to access the sensor for manual cleaning, consider one with environmental sealing (waterproof is also dust-proof).

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What is Carl Zeiss lens in a camera?

Question

I have Sony CyberShot camera, I don't know why they use lens in camera and what is the use of it and actually what is Carl Zeiss lens in camera? Could anyone help me with this problem?

Answer

A lens is needed to focus light on imaging sensor. For example, here's an image taken without lens attached to camera:

For comparison, same scene taken with a lens attached:

Carl Zeiss is a German manufacturer well known for carefully designed good quality optics; see also what makes a Carl Zeiss lens so special in a smartphone (the reasons are similar for a pocket camera).

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Is there a Point and Shoot camera with a Macro function or ability?

Question

I am looking for a simple point and shoot camera with a macro function to be able to take photographs for eBay auctions.

Are there any P&S cameras with this function?

Answer

There are plenty. What I recommend though is a compact with manual controls and for the purpose of eBay, unless you are selling truly miniature items such as insects, they are more recommended than DSLRs and SLDs.

A number of ultra-zooms are actually capable of extremely close focusing distance, as close as 0cm even! Although you will have lighting problems if you get that close, any of those models will do to focus closely. Not only that, the depth-of-field will be much greater than with an interchangeable lens, which is less artistic but arguably better for selling products.

The Canon Powershot SX150 (1cm min) or older SX200 (0cm min) are great choice in a compact form-factor. You can also go with an ultra-zoom like the Canon SX40 or Fuji HS20 EXR. Since these cameras have manual controls, you can set the aperture very small to capture an large depth-of-field. Just make sure to keep the ISO low for getting quality output and using a tripod for stability.

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How important is optical zoom in snapshot cameras?

Question

I want to buy a new snapshot camera. Because i want a new one with geo-tagging, I haven't such a great choice. So the following three cameras are my favorites:

http://digitec.ch/ProdukteVergleichen1.aspx?artikel=209007,207072,208802

• Canon Powershot SX230 HS
• Sony DSC-HX7V
• Panasonic Lumix TZ20

But now they look all very similar to me. The biggest difference I can see as a beginner is the optical zoom. Is this correct? Or is there a more important difference that I can't see?

And if it is only the optical zoom. How much is the difference between 10x and 16x? Do I feel any difference?

Answer

I never tried to hold a 384e mm zoom on such a camera, but as @dpolitt mentioned it might be very difficult. You may want to try that at a store or read up on that.

But, leaving any other image quality aspects aside, I think the wide angle focal length might be much more interesting. 24e to 28e mm, from your given comparison, is quite a difference which cannot be compensated by moving your feet as much as on the narrow angle end. If that is important to your needs, of course.

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Why doesn't the background become blurred when I change the aperture?

Question

I am sorry if my question is too naive, but I am a complete beginner in photography, and I think I still need to understand well what aperture is. I have a Fujifilm S4000 camera, and I know I can't do with it everything that a professional camera does.

I wanted the background of some pictures to be blurred by changing the aperture, but I don't get the results I expected. I think it also has to do with the focal length, am I right? I took two pictures to show you what I mean.

Picture 1 Aperture: f/4 Exposure: 1/2 s Focal length: 7 mm

Picture 2 Aperture: f/10 Exposure: 2.6 s Focal length: 7 mm

I would like to know what settings I can use to get the background to be blurred. I know that with smaller aperture values, the area around the object in focus will be more blurred, but when I change from f/4 to f/10, it doesn't change much.

Answer

There is NO different at ALL because the physical aperture has not changed.

The Fuji Finepix S4000 simulates a small aperture using an ND filter. When you stop-down, the ND filter slides into the optical path. The Aperture written i the EXIF is adjusted to reflect the transmittance of the ND filter but since the size of the opening has not changed, Depth-Of-Field does not change either.

Not only do such cameras have very small sensors and extensive depth-of-field but they are also extremely prone to diffraction. If the aperture was actually stopped down to F/10, images would get quite blurry.

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Is it possible to get custom firmware for digital (pointand shoot) cameras?

Question

Is it possible to manually update a digital camera's firmware?

Is there any organization or do individual people develop custom firmwares?

I am using Samsung SL30 and that lacks allowing manual control over settings. Is a firmware update possible, or is there any other better way?

Answer

Your best bet is to switch to Canon.

• For Canon point & shoots: CHDK.
• For Canon DSLRs: Magic Lantern.

I use both and love them. In particular, CHDK gives manual controls to most P&S, and can also shoot raw on those models that only support jpeg.

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How can I make a very sharp photograph with a point & shoot camera?

Question

I've taken a picture with my Canon PowerShot SX210 IS and the following settings:

• Aperture: F8 (Maximum I have)
• Shutter speed: 1/400
• ISO: 80
• Focal length: 21.1 mm (118mm 35mm-e)

I did increase the contrast a bit through Gimp later on. What other camera settings and timings should I have considered to make this picture sharp?

Please note: with this camera, I can't shoot in raw, and post-processing is the secondary concern for me.

EDIT: I zoomed it to 100% and then cropped off 600x600.

And I didn't mention previously that I had used manual focus. And also, ALL the broken chairs together are the subject.

Answer

f/8.0 is often the "sweet spot" for lenses on 35mm SLRs however on a small sensor camera like a Canon PowerShot that aperture is probably causing diffraction - there's a good reason the aperture doesn't go any smaller than that!

Light spreads out when passing through a small opening like the aperture on a camera and this results in loss of sharpness. The smaller the hole the more spreading you get, so there comes a point where stopping down a lens results in lower peak* sharpness. Due to compact lenses having (and requiring) shorter focal lengths, f/8 on a compact will result in a smaller opening than f/8 on an SLR, therefore you will get more diffraction.

*I said peak sharpness, as average sharpness can increase after the point where diffraction sets in due to increases in depth of field. However if you don't need the depth of field, try shooting at f/4 instead.

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What should I do about Canon PowerShot “Lens error, restart camera”?

Question

I've had a Canon PowerShot A1100 IS camera for almost a year now.

About a week ago, I went on a trip, took pictures the whole trip, everything was ok.

When I got home, and tried to turn the camera to move the pictures to my PC, I got an error: "Lens error, restart camera"

The lens doesn't even start to open, doesn't make any sounds of trying even.

What can I do to fix this?

Answer

Lens errors are fairly common. Usually it's sand or grit interfering with the lens extension mechanism. Or the camera's been dropped with the lens extended. Or the camera has been powered on, but the lens had been blocked preventing its extension.

I have written a blog post about some things that you can do to try to correct it. They only seem to work for about 50% of lens errors, but they're worth a try.

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How can I get nice, vivid colors in food photography without blown-out brightness from the flash?

Question

Whenever I click pictures of people and food using flash, the whole picture becomes bright. When I click without flash, the camera takes in the light from the surroundings and gives me a monotonous and dull colour pattern, particularly when photographing food..

I was trying to capture photos that retain the colour pattern but make the colours more vibrant. Is it possible to achieve this without h post-image processing via editing software? What camera settings or technique should I use to improve my results?

My P & S Camera is Samsung i8.

Answer

I'd suggest you look at using exposure compensation. If your pictures are too bright, then go ahead and use the flash, but turn the exposure compensation down (-.5 or -2/3 for a start). This tells the camera you think it's too bright and it will adjust down.

You can get very dull colors if the light is too low, or if the flash is too bright and washes everything out. If you get the exposure (brightness) right, the colors should be much more vibrant.

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Do digital cameras lose picture quality over time?

Question

For some reasons when I look at my first pictures from my camera (DSLR), they look stunning. I know it could be just psychological. Another friend told me that her camera was really good when she bought it fours years ago (10 MP), but now it is just ok. I see her P&S very blurry in indoors (almost like phone quality pictures).

A quick search yielded this yahoo answer, which is actually not bad. That answer can be summarized as: not really, but some things make image quality worse. Listed factors include:

• Dust accumulation on the sensor (blamed for "resolution loss, pixels of false colors, noise, spots")
• Worn-out moving parts leaving the sensor out of alignment ("focus images, blurry and distorted images")
• Improper maintenance leading to "blown-out receptors on the sensor" (which lead to "blank spots on the image, false-color pixels and resolution loss")
• Dust in the lens ("noisy, blurry and distorted images")
• Scratched or destroyed lens coating ("distortion or false colors due to ultraviolet and infrared radiation reaching the sensor")

Is there any truth to it? What should I be careful for proper maintenance?

Answer

Practically speaking, digital cameras do not lose quality over time.

Some factors can come into play such as:

• Equipment can wear causing it to be out of spec
• Environmental factors such as dirt, sand, dust, moisture can degrade quality
• Heat or excessive use(causing heat) can cause all electronic devices to experience wear
• Other regular use issues from dropping, lack of cleaning, etc

But overall, these things should hardly turn a great looking 10MP point and shoot camera into a 640X480 resolution cell phone.

Maintenance, is an entirely new question if you would like to ask or search for that.

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What's the fastest memory card that can be used with a Canon S95 (P&S) digital camera?

Question

The S95 can apparently accommodate any of the following: SD/SDHC Memory Card, SDXC Memory Card, MultiMediaCard, MMCplus Card, HC MMCplus Card.

Which one is going to be the fastest? I really want to minimize the time to take photos.

Of those choices, I've only used/heard of Secure Digital, so if I had to just pick one at random it would be one of those. "Class 10" SD sounds like the way to go.

Bonus questions: what's the safest bet as far as...

• working in a standard/off-the-shelf card reader?
• longevity?

Answer

Plain SD cards top out at 2GB; SDHC (Secure Digital High Capacity) gets you between 4GB and 16GB; SDXC (Secure Digital eXtended Capacity) gets you from 32GB to 2TB. In practical terms, you're going to be using SDHC cards most of the time -- under 4GB is kind of limiting, forcing you to carry a spare or two, and anything more than 16GB is too expensive to be practical unless you're dealing with a very-high-resolution camera and recording raw data.

The speed of the card is a separate deal. It's not directly related to the capacity.

As for MMC (MultiMedia Card), it's an obsolete format. The SD family shares the same physical layout and electrical contacts, so most SD card devices can also use MMC if you have old cards lying around.

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How can I improve my food photography when limited to a point and shoot?

Question

Previously I have used a Sony DSLR A580 camera along with its 50mm 1.8 lens to take pictures of food. Personally, I really liked that lens. At the moment, I am back to my old Samsung i8 Point and Shoot Camera and am interested in getting close to similar results like those attained from the Sony for photographing food. There are various presets available in the Samsung, but none of them are as good. Kindly drop in your suggestions that would help me improve my shooting skills while photographing food with my Samsung.

I could not provide a similar image for comparison of both the cameras (as Sony A580 is better than my point and shoot any day), but just presented an idea of what I am trying to capture.

PS: Sorry if the food is mouth-watering. :P

Answer

Actually a point-and-shoot is one of the best tool for taking photos for food.

I usually have a DSLR and a point-and-shoot with me, when I want to take photos of food however, I usually use the point-and-shoot thanks to its macro mode.

Most of us shoot our plate of food top-down, framing the shot so that the whole plate is included.

Sorry but that can quickly become boring after 5 shots.

Macro mode is usually found on point-and-shoot. DSLR on the other hand has very limited macro ability until you actually go spend some money on a macro lens.

That is why I prefer using my point-and-shoot! It can shoot the details! I can focus as close as 3 or 4 cm and get very nice photo of my food. My point-and-shoot has a flip-out screen so I can shoot from all kinds of angle.

I can shoot across the plate horizontally without leaving my chair and ducking by the side of the table. I can fill the entire photo with the actual food showing its texture.

As a bonus, usually its easy to get the food in focus since point-and-shoot has a high DOF.

Trust me, a point-and-shoot is better than a DSLR with a kit lens when it comes to food.

You need to get the White Balance right, and you need to light the food well. The best light is when you are eating right next to a huge and bright window at day time.

At night, however, you must find ways to create a soft and pleasing light, which usually involves the use of an external flash. This is not an option for you it seems so I will just leave it.

You also want to make your food look YUMMY. If it is hot food you are shooting, steam will be a plus. Food when freshly prepared are usually shinny since they are wet or there are oil, so if you leave it for too long it will become dull and it will not look nice.

There are things that you can do to create steam and make your food shinny, two simple ways are:

• light a cigarette and place it behind the food
• using a spraying bottle, spray oil on your food to keep it looking fresh

Of course, these may not be the best thing to do when you are planning to actually eat it, but you can definitely keep in mind and try these out when you are allowed to

Lastly food photography actually is very often fake. Ice cream made of clay.... boiling water is actually ice cold with air bubbles manually pumped into it.... etc

So be creative. Good luck!

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Should I buy a DSLR to get started?

Question

I'm really interested in getting into serious or even professional photography. I've read some articles about fundamental concepts like aperture, exposure, ISO sensitivity, etc., and I want to get the feeling of how changing different setting affects the resulting picture.

My point-and-shot camera has a manual mode but it seems like no matter what kind of settings I select, I always get worse results then if I shoot in auto mode.

Some people claim that manual mode on point-and-shoots is a joke. Should get a "real camera"?

Answer

You might want to try borrowing or renting a camera first. Even the cheapest DSLR will cost several hundred dollars, which can be a lot of money if you aren't sure it is right for you.

That being said, DSLRs now are a lot better than they were in pure auto mode, which can make it pretty easy to jump right in. I went from a P&S to a DSLR not all that long ago and really enjoyed it pretty much right away.

One big consideration when thinking about switching to a DSLR is the pure size of the camera. You will no longer have something you can stick in a pocket or throw in a bag. They are much bigger, much heavier and much more fragile. They are also a lot more expensive to buy, repair and upgrade.

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What features really matter in a point and shoot camera?

Question

I am planning to buy my first new digital camera. Now I am too confused for more than 20 days about how I can choose a camera.

I want to use the camera for domestic purpose.

The Canon IXUS 220 HS looks good but it is only 12 MP and only 5X zoom. But there is a also the Canon A3300 that is 16 MP.

So I don't know what is the basis of selecting a camera. What is Image Stabilization? When should I buy a CMOS sensor camera? How much Optical Zoom is sufficient? How much does noise matter in the camera?What about if the camera has HD video recording, and if not, how much will that lack affect viewing on my 32 inch TV?

The cameras I'm currently looking at are Nikon s3100, Canon IXUS 220 HS, Canon IXUS 110 HS, Canon A3300, and Sony W370/B. This will be my first camera and I can't take any risk because I cannot afford a new one in the next few years.

Answer

I would put the number of megapixels at the bottom of the priority list. Megapixels matter, but once you get past about 10 you'll have enough for anything you're likely to do. In particular there wont be a noticeable difference between 12 and 16, theoretically you'll be able to print a 16MP image 15% larger, but that's only if the lens resolves more detail and that detail is not lost to noise.

Image stabilzation prevents blur due to camera shake when you take a photo. It becomes very important the longer the zoom lens. With a 5x it's probably not important but once you get 10x or more you should definitely look for a stabilized model. How long a zoom you need is really up to you.

All small sensor point and shoot cameras will produce noisy images in low light, it's just something you need to be aware of and plan your shooting accordingly.

HD video is a useful feature, I've seen some really good quality clips from this sort of camera, so if you plan to take videos at all I'd look at one that records HD.

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Is it possible to take shallow depth of field photos with point-and-shoot cameras?

Question

I have an Olympus 770SW compact digital camera, and in macro mode I can manage to achieve a blurred background, if the background is far enough away (over a metre). Can this be done when taking non-macro pictures, and if not, is there a way to simulate it?

---

Merged: How to blur the background using a super-zoom camera?

When I shoot portraits with my brother's Nikon D90, this is quite easy to fade out the background. But with my Fuji HS10, super-zoom camera, I haven't been able to take such photos yet. I choose a large aperture for my camera but it still doesn't work. I know that standing further and zooming will result in a smaller depth of field. Why DSLR cameras are so much better in this area? Why zooming make the depth of field smaller? What are the general recommendations to do the job using a super-zoom?

-- Moshen

Answer

There's a good answer from Brian Auer, which I'll reproduce here, as it pretty much covers the problem you're trying to solve:

Ooh, good question. Yes, but how much will depend on the camera.

If the camera has manual controls for aperture, that definitely helps. It also helps if the camera has zoom, as most P&S cameras do. The problem with creating a shallow depth of field comes from the fact that the sensor is so small, and as a result the lens is close to the sensor — thus creating very small focal lengths. My P&S has a focal length range from 6mm to 18mm — which is very small. They create an effective focal length much higher due to the small sensor size. As I said in the tips, a short focal length will produce an image with nearly everything in focus.

So to blur the background using a P&S, you’ll get your best results if you zoom in all the way, focus on something close (you don’t want to focus out to infinity), and have a background that is much further away. So your two points of control are focal length and subject distance. I just gave it a shot with my camera, and it does work.

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How to photograph panning with a point and shoot camera?

Question

I have recently learnt about panning photography on the internet and I was curious about capturing one myself,

But as an amateur I just own a Point and shoot camera,

I have experimented through it thoroughly and the only scene mode with longer shutter speed is Fireworks mode(4s),

But when I used this mode to take a panning photograph, all I got was an Over Exposed image,

How can I take a panning photograph with a point and shoot camera?

Answer

You still need to expose your photograph correctly. So if you're taking a panning photograph in bright light you have to either use a very narrow aperture or a filter, or both. Of course with a P&S camera, both those are difficult: you may have no control over the aperture at all, and there may be no easy way to attach a filter. If that's the case, you'll have to take your panning photographs in darker lighting.

You don't need ultra-long shutter speeds like 4 seconds, though: my picture here was only 1/15 of a second. If you are closer to your subject and it's moving faster, you can probably get away with an even faster shutter speed.

One thing you could try, although I've never tried this and it may be too awkward to pan steadily, is hold your sunglasses in front of the lens as you pan, as a makeshift neutral density filter.

Finally, if you try taking panning photographs in darker light in order to achieve the longer shutter speeds, your camera will probably increase its ISO to prevent camera shake, which is the opposite of what you want (since panning is, in one sense, controlled camera shake). If your camera has a mode that lets you force the ISO to its lowest value, you probably want to use that mode.

Of course, I hope you've also read this answer -- maybe all you need to do with your camera is leave it in Auto mode, zoom in as far as you can, and take pictures of nearby, fast-moving objects.

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