7D, 5D classic, and 5D2 noise and detail

Well, my results are preliminary but I've finally run the comparison shots with the three cameras at 800, 1600, 3200, and 6400 (the 5D doesn't have 6400 so I underexposed 3200 by 1 stop and pulled it up in post-processing).

I've only compared the RAW files in DPP so far and here are my observations from comparing the ISO 3200 shots.

I took all shots at the same ISO, shutter speed, and aperture settings. I used the 70-200 lens, tripod mounted with the 2-second timer and mirror lockup. On the 7D, I shot at 70 mm, and on the two 5's, I had the focal length set at 110 mm. Not quite a perfect 1.6X, but very close.

I had to move the lighting back a bit with the 5D because it is more sensitive than the other two. At ISO 800 and f/8, the 7D and 5D2 needed 1/10 sec shutter speed, while the 5D metered at 1/13 sec. Instead of using different shutter speeds, I moved my lights back 3 feet or so, being careful to keep their direction the same. It would not have been fair to overexpose the 5D's shots by 1/3 of a stop as this would have given it an advantage.

Once the shots were taken, I loaded all the results into the computer and opened the ISO 3200 shot from each of the three. They appear to be equally exposed to the eye, and to the histogram so my lighting adjustment was correct. Next, I made sure that all my settings (sharpness, picture style, etc.) were the same and that I had shot all 3 with "incandescent" white balance.

I carefully compared all the shots at 100% in their native noise reduction states - none on the 5D (doesn't have NR for high-ISO), and Low on both the 7D and 5D2 (this is how I use them). I noted the following default settings on the DPP adjustment sliders from each camera at 3200:

5D Lum - 2; Chrom - 0
5D2 Lum - 5; Chrom - 6
7D Lum - 4; Chrom - 11

At these settings, the 5D2 is the cleanest followed by the 7D and then the 5D. The 5D2 also exhibits considerably more micro-detail even in its native resolution ( I have not resized anything yet). The 7D looks softer than the 5D2, and slightly softer than the 5D (perhaps a little tiny bit less contrasty). But, very small text is easier to read on the 7D due to the larger view on the screen ( higher resolution) compared to the 5D. When I resize them to equal pixel dimensions, I'm certain that the 7D will actually retain more microdetail.

Next, I made some adjustments to the NR settings in DPP. The first thing I noticed is that Canon's choices for NR in the "Low" setting on the 5D2 and 7D are pretty appropriate for each. I also noticed that the 5D reacts to rather low settings on the NR adjustment sliders in DPP.

I adjusted the settings in DPP to get visually equivalent amounts of noise in the shadow areas. These are the settings I came up with (there is a margin of error here):

5D - Lum - 2; Chrom - 3
5D2 - Lum - 4; Chrom - 5
7D - Lum - 4; Chrom - 9

At these settings, the detail presented by the 5D2 was still superior to both the 7D and 5D. The 7D still looked a little soft compared to the 5D2 but held more detail than the 5D by virtue of it's greater resolution.

My third test was to turn both the Luminance and Chrominance NR sliders to 0 on all 3 cameras. At this setting, the visual shadow noise was lowest in the 5D2, but the 5D seemed to be slightly cleaner than the 7D in the shadows. The 5D2 held its detail very well, and both the 5D and 7D were less detailed as before. The 5D held microdetail well and the 7D was slightly softer as before, but it's resolution advantage again made the fine print easier to read on the 7D.

My next test on this will be to return all 3 cameras to the NR setting selected by Canon when in-camera NR is set to "off" (these are not 0 on the 5D2 and 7D). I will convert them to JPG in DPP and then down-rez the 5D2 and 7D to match the pixel dimensions of the 5D. I should be able to crop the results and post them.

I have to say that it's pretty difficult to choose which NR settings to use before converting to JPG. It might seem fair to set all 3 cameras to "0", but that would remove the defaults that Canon puts on the 7D and 5D2. Plus, I really don't know if the 5D has some other type of in-camera high-ISO noise reduction that doesn't translate into DPP's slider settings. I've also considered setting all 3 to what appears to be visually best but I'm not sure that my choices would be best either. I could use ACR and convert them in PSE-7 instead but I like to use DPP since it matches what Canon has chosen for NR (for better or worse).

Stay tuned...

..tuned.

thanks for sharing this with us...

how about an iso test at 100, 200, 400, 800, etc?

mikekelley wrote in post #8927145
how about an iso test at 100, 200, 400, 800, etc?

+1.

The diffraction limit of the 7D is f/6.8, so testing it at f/8 resulted in a decrease from the maximum sharpness.

Thanks for doing this review. Perhaps you could post links to the high-res files?

mikekelley wrote in post #8927145
how about an iso test at 100, 200, 400, 800, etc?

Arrrrgghhhh....

That'll be for another day!

I do have 800, 1600, and 3200 plus 6400 but I'm only going to put up 3200 for tonight. It's getting late here in the eastern time zone for starting another round of images.

I intend, in the future, to set up a scene where I have to pull up shadows at ISO 400. I want to see how much latitude the 7D has.

One small point, I don't think pulling back the lights for the 5D is reasonable. If the 5D is 'more sensitive' as you noted this simply means that the ISO labels on the 5D are not aligned with the other two cameras. By making it shoot a darker scene (moving the lights) you are fixing an arbitrary value (the ISO label) and varying a constant (the actual light). This is not good methodology.

geekyrocketguy wrote in post #8927265
The diffraction limit of the 7D is f/6.8, so testing it at f/8 resulted in a decrease from the maximum sharpness.

Thanks for doing this review. Perhaps you could post links to the high-res files?

I don't have the full files up at this point. The difference in visible diffraction between f/6.8 and f/8 is negligable, but I'll consider that for the next test. The downside to opening up the aperture further is that the shallow depth-of-field becomes an issue when testing sharpness and acuity, especially with the full frame cameras.

EDIT: I will test more tomorrow, and I will shoot at f/5.6 just to eliminate that variable.

JeffreyG wrote in post #8927290
One small point, I don't think pulling back the lights for the 5D is reasonable. If the 5D is 'more sensitive' as you noted this simply means that the ISO labels on the 5D are not aligned with the other two cameras. By making it shoot a darker scene (moving the lights) you are fixing an arbitrary value (the ISO label) and varying a constant (the actual light). This is not good methodology.

The ISO on the 5D has been shown, like other early Canon cameras, to be 1/3 stop more sensitive than the standard. This is documented on some Canon camera reviews on DPReview and proven through comparisons by others. I wouldn't really call it an arbitrary value in this case, but I certainly see your point. I can't hardly expose the 5D shots at 1/3 stop brighter and call the test fair. I considered raising the shutter speed on the 5D by 1/3 stop, but as soon as people read the EXIF, the test would be questioned. I may re-do at least the 3200 test and try that.

The exposures are identical in terms of the brightness of the captured image. That was my goal.

Tom W wrote in post #8927337
The ISO on the 5D has been shown, like other early Canon cameras, to be 1/3 stop more sensitive than the standard. This is documented on some Canon camera reviews on DPReview and proven through comparisons by others. I wouldn't really call it an arbitrary value in this case, but I certainly see your point. I can't hardly expose the 5D shots at 1/3 stop brighter and call the test fair. I considered raising the shutter speed on the 5D by 1/3 stop, but as soon as people read the EXIF, the test would be questioned. I may re-do at least the 3200 test and try that.

The exposures are identical in terms of the brightness of the captured image. That was my goal.

You should shoot the 5D at 1/3 stop lower ISO and simply note that this is what creates the same final image.

ISO values used by the cameras are not perfect, but in day to day shooting what matters is the real sensitivity. If I'm shooting my camera A and ISO 1600 and camera B at ISO 2000 and getting the same final image (other settings equal) then the truth is that 1600 on A = 2000 on B. The numbers are meaningless.

DPReview has struggled with this same issue recently on micro 4:3 cameras. The Olympus EP-1 needs a shutter speed twice as long at ISO1600 as the Panasonic GF-1 to yield the same exposure. Head to head the Oly seems cleaner at ISO1600 (duh!). Shoot them at the same final exposure (equal aperture and shutter speeds) and the noise performance is identical.

OK, I have some visual evidence to post.

First, the test scene. Nothing fancy - just a bunch of stuff lined up with some incandescent lighting. I purposely put some fine print up to show some of the detail acquisition of the 3 bodies.

subscribing. thanks for doing this Tom!

JeffreyG wrote in post #8927357
You should shoot the 5D at 1/3 stop lower ISO and simply note that this is what creates the same final image.

Can't do that at 3200 - the 5D doesn't have the 1/3 stop ISO settings above ISO 1600 so only full stops are available. I guess I could move the 7D and 5D2 to ISO 4000 for the comparison, but since they're supposed to be the accurate ones in terms of ISO, I don't want to change that.

Yes, that's why they test (or used to test) the ISO accuracy. Early Canon DSLR cameras, I believe up to the Rebel XTi, were consistently 1/3 stop more sensitive than the setting indicated. Canon corrected this and later cameras are correct. It's always a stumbling block when trying to compare high-ISO noise between Canons from the two eras. I wrestled with it when I got the 5D2 and I'm wrestling with it now.

Tomorrow, I will re-test at 3200, but I will have to change the shutter speed because I can't move the ISO on the 5D 1/3 stop. I don't want to mess with the aperture because I want to eliminate DOF as a factor.

I also want to test at f/5.6 instead of f/8 to eliminate the possibility that diffraction is having a significant effect on the 7D's results. The output at 100% of the original resolution did look a bit soft at f/8 and I want to be sure that it wasn't something I did. I may also realign my test setup so that I'm in the middle of the zoom range for all 3 cameras.

I will check microadjustment on the 7D to the 70-200 prior to the test as well. I spot-checked the 7D with 4 or 5 lenses when I got it and they were all right on. Don't recall if I did the 70-200 though. If it's off, it's really really close.

Nice!