Another full frame question

Discussion in 'Canon EOS' started by james_martin|9, Jul 18, 2007.

  1. Based on some research, it seems that for long telephoto shooting in low light,
    an APS size sensor might be better than full frame. I do mostly low light long
    range stuff in dance halls and theatres where I am usually maxed out on a
    telephoto. ANy thoughts.
  2. The low light capability of the 5D is excellent. I get great shots at ISO 1000, 1250, and even 1600 with low noise. But you do get the focal lenghth of the lens. So for long-telephoto you must use loger lenses.

    I would think you would want to get closer with a fast lens. Say a 135mm F2, 85mm F1.2, 50mm F1.2, 35mm F1.4 or something like that. Long telephoto lenses tend to be slower F2.8, F4. Those are not the best for low light unless firmly mounted on a tripod.

    The 1.6 crop cameras (30D / XTI) could be a solution. But 1.6 sensor sizes have noticable noise at 800, 1600, & 3200. If you could use a fast lens with a 1.6 crop it might work for you (135mm F2 for example).

    I would examine you existing images. Look at the shutter speed & F-stop. Then figure out what you would get by increasing ISO, or using a faster lens.
  3. The only way that APS is "better" than full frame for telephoto shooting is that shorter
    (lighter, smaller, less expensive) lenses give you the same angle of view.

    In general, full frame sensors with X megapixels should be better in low light due to, or so
    the assumption goes, the possibility of larger photosites. This can lead to a reduction in
    noise, which could be even more important when shooting at high ISO.
  4. I don't see how a APS size sensor would be better than a Full frame sensor in low light. in fact I would have guessed the opposite.. the photosites on the larger full frame sensor are bigger and will have a better ability to create lower noise images with less light.. however the difference is probably negligible.
  5. You should simply try a search on Pixel Density.
  6. As for the 5D versus 30D telephoto debate, which is better depends on how much you end up cropping in to the pictures from the 5D.

    Its like asking whether it is better to use 35mm and crop in camera, or to use 645 and crop in the enlarger. It all depends on how much you crop...except that in this case, the 5D and 30D have different responses to noise, so it is like comparing the two cameras with a different film in each. Ideally, you would not have to answer the question because you'd just get a longer lens for the 645...but it is rarely the case that you have the absolute perfect tool for the job.

    I remember a test on the internet that showed that you will get better image quality from using the cropped sensor in the first plane than you will by using the higher resolution camera and cropping down to the same size. I believe that exact test I saw was by Bob Atkins, and compared the 30D (or the D200?) to the 5D in order to answer this very question.

    I lot of old journalism was shot loose, because focusing wasn't as easy or as accurate before SLRs, and negatives were nice an big. However, that trend faded away as SLRs came in.

  7. William Michael

    William Michael Moderator Staff Member

    Returning to the literacy of question, specifically, and leaving aside `how much do I enlarge post production to get the same angle of view` and `different noise` issues:

    I would prefer a FF body for long telephoto shooting in low light: the viewfinders of FF surely would be brighter, and the job easier to manage for the eye and brain.

    (Long telephoto = > 300mm, Low light = ~ F4 @ 1/60 @ 1600ISO or thereabouts)

  8. Here's Bob's article

    As you can see, the 5D has the slight advantage. If you can afford it, get the 5D. It's an excellent camera.
  9. Method three in the article is your situation, James, and the edge goes to the 1.6x sensor:

    "Center Resolution - Test Method 3

    Here's a series of shots using test method 3, i.e. with the same lens at the same aperture and at the same distance from the subject:

    Canon EOS 5D vs. EOS 20D - Full Frame vs. APS-C Sensors

    As you can see, in this case the 20D image shows more detail. This situation (same lens form same distance) is the situation that nature photographers often find themselves in. They're using their longest lens (typically a 500mm or 600mm, maybe with a multiplier on it) and they're as close to their subject as they can get. They might use a longer lens if they had one, but they don't! Under these circumstances, where you'd have to crop one or both images to the same field of view, results from an APS-C sensor with a higher pixel density (such as the EOS 20D) can give better results than those from a full frame camera with a lower pixel density (such as the EOS 5D)"

  10. Yes, but James was interested in low light performance. That perhaps gives the edge back the the 5D because of the larger photoreceptors.

    It sounds as if we're all splitting hairs. The question becomes: how much do you want to spend on a camera?
  11. For noise at high ISO the larger sensor have the better potential as long as the size of every pixel also is larger.

    For resolution it is more complicated. A high density APS sensor can resolve as much as a larger sensor with the same pixelcount (Mpix), as long as the lens outresolves the sensors ( this is more of a problem for smaller sensors).

    The larger sensor have the advantage in that it can increase both pixel count and pixel size at the same time. More Mpix means higher resolution and larger pixels means lower requirements for the lens.

    Lenses do perform worse towards the edges and corners of the frame, so its possible that you will get worse edge performance on a full frame sensor than on a APS sensor, even when you have more Mpix on the large sensor.

    APS sensors has the advantage of a deeper depht of field at any given aperture, for those who want this behavior.

    The best camera for what you are doing is likely the new Canon D1 MK3 with a APS-H (1,3x crop) sensor.
  12. "Yes, but James was interested in low light performance. That perhaps gives the edge back the the 5D because of the larger photoreceptors."

    But don't forget that 1/3 of the 5D image must be chopped off before you will achieve the same pixel dimensions and framing that the 20D provides. So when you do this, you are getting the full image quality of the 20D, but only 2/3 the image quality of the 5D. Does 2/3 of a 5D file still beat a full 20D file at high ISOs?

    Someone out there with both camera must be willing to do the test.......

  13. Maybe Bob can comment on the ISO he used for his type 3 test. I suspect it was not 3200, which might be appropriate for this question. The 1D mk III would add another set of data for better low ISO performance yet intermediate pixel density between the 5D and 20/30D.

    The other variable in the equation is your lens. There are two issues here: one is the maximum aperture, since you can get the same angle of view coverage at a wider aperture (and hence lower ISO) with the smaller sensor. The other is the focal length. I doubt you are using a 400mm f/2.8. If you are at the long end of say a 70-200 f/2.8, then I think it's clear that you would do better with a larger sensor camera and a longer lens.
  14. Get the 1DmkIII, assuming money is not an issue (which it always is): 1.3x crop factor and the best high-ISO performance available.
  15. Dance halls? Theatres? Sounds like 70~200/2.8 or 135/2 territory to me. If you feel the need for what the natural history fraternity thinks of as long lenses (which is where the Extender versus 1.6-factor debate gets interesting), then what you really need is better access rather than better kit.
  16. "But don't forget that 1/3 of the 5D image must be chopped off before you will achieve the same pixel dimensions and framing that the 20D provides."

    No. That is only true if you are using the wrong lens on the full frame camera.

    (It would be equivalent to use an argument based on full frame being "normal" that a flaw with crop sensor cameras is that you would have to stitch two frames together to get
    the same angle of view. That would, of course, be nonsense. You'd just use the right lens for the shot.)

    If you have a full frame 12 MP camera and a crop sensor 8 or 10 MP camera and you put lenses on them that provide the same field of view (let's say 80mm of the full frame and
    50mm on the crop body) the image quality of the full frame shot has the potential to provide more detail, greater dynamic range, and less noise.

    I'm not saying that full frame is always "better" than crop. Other factors besides detail, DR, and noise level that may sometime be more important.

    For example, if you are shooting at the extreme telephoto end and can't afford, can't obtain, or don't want to carry a larger lens, a crop sensor body can get you the same field of
    view with a shorter, lighter, and less expensive lens. As we've all undoubtedly heard many times, many who photograph birds believe that crop sensor bodies provide more
    advantages than disadvantages for their work.

    On the other hand, if your goal is to maximize DR, low noise, and detail the larger MP count and larger photosites of the full frame sensor will provide an advantage (the size or
    significance of which we could debate) over the smaller sensor. Also, if you are a fan of UWA photography you will have more options with full frame.

    All of that said, the OP asked specifically about "mostly low light long range stuff in dance halls and theatres where I am usually maxed out on a telephoto" and whether "an APS
    size sensor might be better than full frame."

    As In most things, the answer depends a lot of the particular photographer. Is he currently using a full-frame body and considering a move to crop to compensate for the not-
    quite-long-enough telephoto? Does the concept of "better than full frame" include only the issue of focal length, or does it also include noise and ISO? Does he work hand held
    or from a tripod/monopod? And so forth...

  17. Dan,

    Re: "No. That is only true if you are using the wrong lens on the full frame camera."

    The question at hand here concerns using the same lens on the two cameras, not which lens/body is right or "wrong". The poster is curious to know if getting a 30D or the like could prevent him from having to shell out the money for a new lens. The question is whether it is better to use a 5D and crop, or to use the same lens on an APS sensor camera. As I stated above with my 35 vs. 645 analogy, ideally you would use a longer lens on the 5D than using the same lens on the APS sensor. This question does ot concern what is ideal, however.

    Ideally, the 200mm f/1.8 on a Mark III, with a 1.4x extender if needed. (It would still be faster than a 2.8 lens.)

    Or a Nikon 300mm f.2.0 adapted to a 5D, if you want to get crazy.

    Is almost $10,000 a good value for the poster to have the "right" setup, though? Or is $1,000 for a body that might help a little bit more like it? We're not Getty Images here, so the ideal setup is seldom feasible for us.


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