Sensor ISO versus Lens aperture
Jun 9, 2015 11:09:55 #
Gene51 wrote:
Yes. you can either shoot at your current settings... (show quote)
Gene,
I agree that the 5d III would be a better option than the 5D II. However sense he makes no mention of shooting wildlife or birds the 6D might be a better option. It will do everything he wants and is much more affordable. Here is an excellent buy on one:
http://www.adorama.com/ICA6DOB.html
The 6D has newer technology than the 5D III and I think it will handle low light better.
Jim D
Jun 9, 2015 12:43:35 #
mwsilvers
Loc: Central New Jersey
billgrove wrote:
I have been shooting low-light for dance recitals ... (show quote)
I find it hard to understand how you could be getting usable images with that camera and lens combination in very low light with a moving subject and no flash. I would think the results would be extremely noisy, out of focus, or both. Could you post some examples? It might give us some insight in helping you decide on next steps.
Jun 9, 2015 14:29:17 #
amfoto1
Loc: San Jose, Calif. USA
There are actually three primary ways to deal with low light shooting:
1. A camera with inherently lower noise imaging.
2. A lens with a larger aperture.
3. More careful/advanced noise reduction in post-processing.
Or, for that matter, a combination of any two or all three.
I can tell you for sure that a 5DII can render usable images at about one stop higher, maybe slightly more, than your T2i. In other words, if you are happy with ISO 1600 images from your T2i, you'll likely be equally happy with ISO 3200 images from 5DII. I don't have T2i, but do use 5DII alongside a pair of 7Ds which have essentially the same sensor and use the same Digic 4 processor (although 7D has dual processors, to be able to shoot higher frame rates).
The problem with 5DII is that you'll lose a lot of the apparent "reach" of your telephoto lens. It also doesn't have a particularly low-light or action oriented AF system. Besides imaging capabilities, the focus performance in low light is another important thing you need to consider. The good news is that the rather primitive AF of the 5DII is about the same as in your T2i... So if your camera's AF is working for you, the 5DII's probably would too.
My 7D have a much more advanced AF system, far faster and better for moving subjects than the 5DII's. But they are rated the same for low light focusing capability as the 5DII, and I have noticed they actually seem to be slightly less low-light capable. All other things being equal, they are a little more inclined to start hunting when lighting is low. The 5DII slows down a lot, but still manages to focus at times when the 7Ds gave up.
Focusing is also greatly effected by the lens being used. USM lenses give the best AF performance... faster focus acquisition and better tracking of movement (STM lenses are almost as fast and good at tracking, are preferable for video because they are quieter and smoother operating).
Um. Your Sigma 70-300 IS USM doesn't exist. There's no such lens. It's either a Canon 70-300 IS USM... or it's a Sigma 70-300 OS HSM. Either way, it uses the "better" ultrasonic/ring type focus drive.
5D Mark III saw significant improvement in it's AF system, both in terms of speed and tracking, as well as lower light capability. It has 61 AF points, 41 of which are higher performance "cross type", and five of those at the center are "f2.8 enhanced" extra high performance. 6D uses a much simpler 11-point AF system, with only the center one the enhanced/cross-type. But both 5DIII and 6D have especially enhanced low light focusing capabilities (as well as lower noise/high ISO performance even better than 5DII)... they can still focus about -2EV... which one or more stops lower light than most other Canon camera models.
Larger aperture lenses not only gather more light for low light shooting (allowing you to use lower, "cleaner" ISOs)... the additional light also can help AF performance. Many Canon cameras have a center AF point that gives enhanced performance when used with f2.8 and faster lenses (I don't know about the T2i specifically tho...)
A possible problem with larger aperture lenses is shallow depth of field. It may not be possible to use the lens wide open, due to limitations of DoF. Another factor... a lot of lenses aren't their sharpest wide open, give better images quality a stop or so down.
A 70-200/2.8 isn't the only option. In fact, 70-200/4 would give you a full stop more light than your current f5.6 lens. 70-200/4 is more affordable, as well as roughly 2/3 the size and weight. Is 200mm enough "reach" on your T2i? Would it be enough on a full frame model like 5DII?
If you would consider prime lenses instead of zooms, you'd have even more potential. 50/1.4 captures up to 4X as much any f2.8 zoom, or up to 16X more light than your f5.6 zoom! 85/1.8 isn't quite as fast, about 1.33 stops larger than any zoom. And 100/2 or 135/2 each are a full stop faster. All the Canon versions of these are fast, accurate USM lenses, too. But, once again, you have to watch out for depth of field limitations using those large apertures. Most of these work pretty well wide open, too, tho I usually stop down my 50/1.4 to f2 at least.
Even without additional lenses or a different cameras, here are some other things you should try, to get usable images at higher ISOs...
1. Shoot RAW and post-process your own images. RAW files have more latitude for adjustment than JPEGs do. Also, by post-processing your RAW you can apply more advanced noise reduction techniques.
2. Avoid under-exposure like the plague! In fact, it's better to slightly over-expose, than to under-expose at all. If you have to brighten an image in post-processing, that will greatly increase the appearance of noise. It's better to slightly darken the image.
3. Use a more advanced noise reduction software. There are several good ones. Personally I use a Noiseware Photoshop plug-in. Using this I regularly shoot ISO 3200 with my 7Ds... and can make usable images at 6400 with a bit more work. By "usable", I mean I can make high quality prints 8x10/8x12 or smaller from those images. I know folks who have used even higher ISO than me... With even more involved noise reduction techniques in post-processing. One using Noiseware to work on NR in each color channel individually has made lots of usable images as high as ISO 12800 using 18MP cameras like yours and mine.
4. Get closer and "fill the frame" with your subjects as best you can. You want to avoid or at least minimize cropping because that also will magnify the appearance of noise.
5. Don't be overly critical of your images. Viewing an 18MP image at 100% on most modern computer monitors is like making a five foot wide print from it and then viewing it from 18" away. That's rather silly. It's is way, way larger than most people will ever use their images and way closer than you'd ever view an actual print that size. So it's bound to look like crap!
Yeah, it's fine to zoom in for retouching and careful work on images... But when evaluating focus accuracy, noise, and sharpness back off to a more realistic view, ideally to the actual size intended or - in the case of an 18MP camera - perhaps to 25% or 33% at most. This is much more realistic... yet still quite large.
So there really is not a simple, single "this is best" answer to your questions. Personally I do all three... using my 5DII for low light shooting at times, using large aperture (faster) lenses, and apply some extra care in NR during post-processing.
1. A camera with inherently lower noise imaging.
2. A lens with a larger aperture.
3. More careful/advanced noise reduction in post-processing.
Or, for that matter, a combination of any two or all three.
I can tell you for sure that a 5DII can render usable images at about one stop higher, maybe slightly more, than your T2i. In other words, if you are happy with ISO 1600 images from your T2i, you'll likely be equally happy with ISO 3200 images from 5DII. I don't have T2i, but do use 5DII alongside a pair of 7Ds which have essentially the same sensor and use the same Digic 4 processor (although 7D has dual processors, to be able to shoot higher frame rates).
The problem with 5DII is that you'll lose a lot of the apparent "reach" of your telephoto lens. It also doesn't have a particularly low-light or action oriented AF system. Besides imaging capabilities, the focus performance in low light is another important thing you need to consider. The good news is that the rather primitive AF of the 5DII is about the same as in your T2i... So if your camera's AF is working for you, the 5DII's probably would too.
My 7D have a much more advanced AF system, far faster and better for moving subjects than the 5DII's. But they are rated the same for low light focusing capability as the 5DII, and I have noticed they actually seem to be slightly less low-light capable. All other things being equal, they are a little more inclined to start hunting when lighting is low. The 5DII slows down a lot, but still manages to focus at times when the 7Ds gave up.
Focusing is also greatly effected by the lens being used. USM lenses give the best AF performance... faster focus acquisition and better tracking of movement (STM lenses are almost as fast and good at tracking, are preferable for video because they are quieter and smoother operating).
Um. Your Sigma 70-300 IS USM doesn't exist. There's no such lens. It's either a Canon 70-300 IS USM... or it's a Sigma 70-300 OS HSM. Either way, it uses the "better" ultrasonic/ring type focus drive.
5D Mark III saw significant improvement in it's AF system, both in terms of speed and tracking, as well as lower light capability. It has 61 AF points, 41 of which are higher performance "cross type", and five of those at the center are "f2.8 enhanced" extra high performance. 6D uses a much simpler 11-point AF system, with only the center one the enhanced/cross-type. But both 5DIII and 6D have especially enhanced low light focusing capabilities (as well as lower noise/high ISO performance even better than 5DII)... they can still focus about -2EV... which one or more stops lower light than most other Canon camera models.
Larger aperture lenses not only gather more light for low light shooting (allowing you to use lower, "cleaner" ISOs)... the additional light also can help AF performance. Many Canon cameras have a center AF point that gives enhanced performance when used with f2.8 and faster lenses (I don't know about the T2i specifically tho...)
A possible problem with larger aperture lenses is shallow depth of field. It may not be possible to use the lens wide open, due to limitations of DoF. Another factor... a lot of lenses aren't their sharpest wide open, give better images quality a stop or so down.
A 70-200/2.8 isn't the only option. In fact, 70-200/4 would give you a full stop more light than your current f5.6 lens. 70-200/4 is more affordable, as well as roughly 2/3 the size and weight. Is 200mm enough "reach" on your T2i? Would it be enough on a full frame model like 5DII?
If you would consider prime lenses instead of zooms, you'd have even more potential. 50/1.4 captures up to 4X as much any f2.8 zoom, or up to 16X more light than your f5.6 zoom! 85/1.8 isn't quite as fast, about 1.33 stops larger than any zoom. And 100/2 or 135/2 each are a full stop faster. All the Canon versions of these are fast, accurate USM lenses, too. But, once again, you have to watch out for depth of field limitations using those large apertures. Most of these work pretty well wide open, too, tho I usually stop down my 50/1.4 to f2 at least.
Even without additional lenses or a different cameras, here are some other things you should try, to get usable images at higher ISOs...
1. Shoot RAW and post-process your own images. RAW files have more latitude for adjustment than JPEGs do. Also, by post-processing your RAW you can apply more advanced noise reduction techniques.
2. Avoid under-exposure like the plague! In fact, it's better to slightly over-expose, than to under-expose at all. If you have to brighten an image in post-processing, that will greatly increase the appearance of noise. It's better to slightly darken the image.
3. Use a more advanced noise reduction software. There are several good ones. Personally I use a Noiseware Photoshop plug-in. Using this I regularly shoot ISO 3200 with my 7Ds... and can make usable images at 6400 with a bit more work. By "usable", I mean I can make high quality prints 8x10/8x12 or smaller from those images. I know folks who have used even higher ISO than me... With even more involved noise reduction techniques in post-processing. One using Noiseware to work on NR in each color channel individually has made lots of usable images as high as ISO 12800 using 18MP cameras like yours and mine.
4. Get closer and "fill the frame" with your subjects as best you can. You want to avoid or at least minimize cropping because that also will magnify the appearance of noise.
5. Don't be overly critical of your images. Viewing an 18MP image at 100% on most modern computer monitors is like making a five foot wide print from it and then viewing it from 18" away. That's rather silly. It's is way, way larger than most people will ever use their images and way closer than you'd ever view an actual print that size. So it's bound to look like crap!
Yeah, it's fine to zoom in for retouching and careful work on images... But when evaluating focus accuracy, noise, and sharpness back off to a more realistic view, ideally to the actual size intended or - in the case of an 18MP camera - perhaps to 25% or 33% at most. This is much more realistic... yet still quite large.
So there really is not a simple, single "this is best" answer to your questions. Personally I do all three... using my 5DII for low light shooting at times, using large aperture (faster) lenses, and apply some extra care in NR during post-processing.
Jun 9, 2015 15:03:07 #
sloscheider wrote:
the 2.8 will give you 2 stops of extra light and help with auto focus in poor lighting conditions. If you have the money I'd go for the lens.
:thumbup:
Jun 9, 2015 15:12:49 #
billgrove wrote:
I have been shooting low-light for dance recitals ... (show quote)
The is another option. DxO Optics Pro Elite has superior noise reducing capability. As long as you shoot in RAW. If you shoot JPG, the noise reduction is no better than any other noise reduction.
It does a very intensive mathematical method of identifying and removing noise that is just unbelievable. It also does not remove the fine detail.
It does put a big load onto your PC to do the processing.
Jun 9, 2015 19:19:41 #
billgrove wrote:
I have been shooting low-light for dance recitals ... (show quote)
For better images - period - you will need a better LENS ! The only zoom that goes to 300mm 2.8 is the Sigma 120-300. Even with OS you will need a monopod with good technique. Personally, as mentioned, I would use the DXO software with an excellent f4 lens - like the Sigma 100-300 f4.
Jun 9, 2015 19:38:51 #
JimH123 wrote:
The is another option. DxO Optics Pro Elite has superior noise reducing capability. As long as you shoot in RAW. If you shoot JPG, the noise reduction is no better than any other noise reduction.
It does a very intensive mathematical method of identifying and removing noise that is just unbelievable. It also does not remove the fine detail.
It does put a big load onto your PC to do the processing.
It does a very intensive mathematical method of identifying and removing noise that is just unbelievable. It also does not remove the fine detail.
It does put a big load onto your PC to do the processing.
As much as I highly respect the DXO program . . . it is a misnomer to believe that any kind of post processing can correct poor lens quality or under/over exposure . . . even when shot in RAW.
Your situation calls for a better, faster lens, that will allow you to shoot at a lower ISO. With a faster lens you will also enjoy the benefit of faster more accurate focusing in subdued light.
My opinion . . . go for the best glass you can muster . . . then down the road consider upgrading to a better camera. Top glass like the "L" series for Canon, is an investment for your photographic future. It is never a mistake to buy the best glass.
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