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Old Sep 2, 2004, 5:37 PM   #1
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I have been consumed of late in trying to find a digital camera that is able to take good photos in very dim light.

style="BACKGROUND-COLOR: #000000"I understand the basic idea behind the aperture--larger aperture in"fast" camera = better shots in low-light conditions (say, a shot of crowded, low-litbar).

style="BACKGROUND-COLOR: #000000"Now, does that mean that a camera with a large maximum aperture--say, f-2.0 will ALWAYS take better low-light shots, all else being equal? And what else could makea difference--i.e., is it possible to have a camera with a slightly smaller max aperture that takes better night shots than another with a larger aperture?

style="BACKGROUND-COLOR: #000000"I currently have a compact digital camera (Canon S400) with a max aperture of f-2.8. I feel that it's not really doing the trick with low-light shots, because people move and get blurry (and there is some amount of noise, though I understand this is a separate issue).

style="BACKGROUND-COLOR: #000000"I am looking at supposedly higher-performing cameras that boast night shot presets and manual controls for the shutter speed and aperture--e.g. the Casio Exilim EX P600. But it still has a max aperture of f-2.8. So will it take better night shots?

Thanks in advance for helping me solve this question!
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Old Sep 3, 2004, 7:38 PM   #2
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It's not simplya matter of having a lens with a larger aperture opening. In order to expose a picture, be it on a digital sensor or file, you must achieve the correct amount of light. The factors that affect the amount of light that reach your sensor are shutter speed and aperture. Additionally, the ISO setting (which determines the sensitivity to light just as the ISO for film) will change the factors. Larger ISO's increase the sensitivity to light, but also increase the amount of noise (electrical interference). Exposure is probably the biggest misunderstood element of photography but one of the most important ones to get right.

Here are a few references that may help you with this:

http://www.photo.net/learn/making-photographs/exposure

http://www.luminous-landscape.com/tu...exposure.shtml


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Old Sep 18, 2004, 3:46 PM   #3
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I agree...but I also would like to add that natural low light is better than any other low light source provided there is enough contrast for good focusing. The best camera I ever used for this was the Olympus C-2100UZ.
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Old Sep 18, 2004, 7:11 PM   #4
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olaf wrote:
Quote:
I have been consumed of late in trying to find a digital camera that is able to take good photos in very dim light.

I understand the basic idea behind the aperture--larger aperture in"fast" camera = better shots in low-light conditions (say, a shot of crowded, low-litbar).

Now, does that mean that a camera with a large maximum aperture--say, f-2.0 will ALWAYS take better low-light shots, all else being equal? And what else could makea difference--i.e., is it possible to have a camera with a slightly smaller max aperture that takes better night shots than another with a larger aperture?
Well, your comment about "all else being equal" would be the key there. Yes, if all else was equal (same ISO speeds, same lighting, same image processing, same sensor, etc.), then the larger aperture would give you faster shutter speeds, and you should get better photos in a low lit bar,if motion blur is your primary problem.

f/2.0 is twice as bright as f/2.8. So, your camera could use shutter speeds twice as fast (if everything else was equal).

Quote:
I currently have a compact digital camera (Canon S400) with a max aperture of f-2.8. I feel that it's not really doing the trick with low-light shots, because people move and get blurry (and there is some amount of noise, though I understand this is a separate issue).

I am looking at supposedly higher-performing cameras that boast night shot presets and manual controls for the shutter speed and aperture--e.g. the Casio Exilim EX P600. But it still has a max aperture of f-2.8. So will it take better night shots?
IMO, it would take worse shots in your low light bar scenario. The 4MP 1/1.8" CCD used in your S400 has larger photosites for each pixel compared to the Casio, and has one of the best noise profiles you'll find in a non-DSLR model at higher ISO speeds. The "night shot" presets for the Casio are simply designed to allow it to take long exposure night photos with preset settings. This is similar to the slow shutter mode on your S400. The manual controls won't offer any benefit either (your S400 will already be selecting the largest available aperture in a low lit bar).

Both cameras use a "dark frame" subtraction method of noise reduction for long exposures. This has nothing to do with the random noise you'll see at shorter shutter speeds (as in a low lit bar). It's only designed to reduce the appearance of hot pixels that will appear in longer exposures.

To do significantly better in a low lit bar, you're going to need to either use your flash; or get a camera with a brighter lens and/or better noise profile at higher ISO speeds.

A DSLR is probably the best choice. These can shoot at much higher ISO speeds with lower noise levels. About the least expensive one you'll find right now is the Canon Digital Rebel. You'll also want a bright lens to go with it. I'd suggest something along the lines of the 50mm f/1.8 lens (under $100.00). It's not a zoom lens, but it is very bright.

If this is outside of your budget, you may want to try something like the Canon G3. It's got the same 4MP 1/1.8" CCD as your S400. However, it's lens is much brighter (f/2.0 at full wide angle, only stopping down to f/3.0 at full zoom). So, it would be able to use shutter speeds at least twice as fast -- depending on the amount of zoom you used, for equivalent ISO speeds and lighting.

The G3 has been discontinued for a while now, so it may be difficult to find. I personally think this sensor does a bit better in low light, compared to the newer sensors in the newer models. Another model to look at would be the Sony DSC-F717. It's got a very bright lens, too (f/2.0 at full wide angle, only stopping down to f/2.4 at full zoom). It would be easier to find.

You willalso need to increase ISO speeds with any camera you use to reduce motion blur when you are not using a flash. Each time you double the ISO speed, the camera can use shutter speeds twice as fast. This will increase noise significantly in a non-DSLR model (like your S400, theG3 or the DSC-F717). However, you can get good tools to reduce the appearance of noise. Here are a few:

http://www.neatimage.com

http://www.picturecode.com

http://www.imagenomic.com (this one has a free version)

BTW, try not to use any zoom with your S400 when shooting in low light (and the same thing goes for most compact cameras). More than twice as much light reaches the sensor through your lens at wide angle, versus full zoom.
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Old Sep 28, 2004, 5:04 PM   #5
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JimC, thanks for that message; it was very helpful. I know this is going to sound totally unrealistic, but is there a compact camera that has a fast lens and can take low-light shots? The G3 is big (my sis has one) and the Sony is enormous. I feel like I'll never take something like that out with me in the first place, so it sort of defeats the purpose of buying a new camera... Anyway, if you can think of some compact cameras out there that outperform the S400 enough to warrant a new purchase, I'd much appreciate it--I thought the Casio P600 might do it, but apparently not...

THanks again for your thoughtful comments!
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Old Sep 28, 2004, 8:07 PM   #6
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Well... a camera the size of the G3 is considered compact. :-)

I'd consider the models you're looking at subcompact.

Unfortunately, you need a little larger lens design for a given sensor size to get a brighter lens.

The vast majority of compact and subcompact cameras have lenses that start out at about f/2.8 at wide angle, and stop down to around f/4.9 at full zoom.

The newer "G" series Canon models start out at f/2.0 at wide angle (which is twice as bright as f/2.8 ), and only stop downto f/3.0 at full zoom. The Sony DSC-F717 I mentioned also starts out at f/2.0 at wide angle, and only stops down to f/2.4 at full zoom.

The aperture scale (in one stop increments) goes F/1.4, F/2.0, F/2.8, F/4.0, F/5.6, F/8.0, F/11, F/16, F/22... With each one stop move to a smaller aperture (represented bylarger f/stop numbers), you will need shutter speeds twice as long for proper exposure for any given lighting condition and ISO speed setting.

Also, non-DSLR models can't do as well at higher ISO speeds because of their very tiny sensors. A DSLR can shoot at much higher ISO speeds with lower noise levels. So, it's very difficult to find any non-DSLR model that does real well in existing light condtions without a flash of moving subjects.

Even models like the Sony DSC-F717 and Canon G3 I mentioned would be considered very marginal for the conditions you want to shoot in (depending on the viewing and print sizes needed, and the quality of the images you need).
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