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7D:
blackpoint 2047, full-well 15303, StdDev blackframe (mask area only choice to measure for now) 5.41, DR =11.26 'per pixel' or 11.82 in 8.2MP 20D/30D normalization
table:
KEY
Camera:
DR 'per pixel', DRn normalized to 8.2MP, ISO at which max DR (but not necessarily max 18% gray SNR) occurs, pattern banding comment at ISO of highest DR (high pattern banding may reduced real-world effective DR)
5D2:
11.24, 11.9, ISO100, quite major pattern banding
7D:
11.26, 11.8, ISO200, appears to be very low pattern banding
50D (typical copy tested):
11.07, 11.5, ISO200, quite major pattern banding
40D (exceptionally good copy tested):
11.32, 11.5, ISO200, relatively moderate pattern banding
20D (exceptionally poor copy tested):
10.56, 10.6, ISO100, not characterized but prob intermediate
Looking at the screen in 1:1 view the 40D will seem to have the best DR, followed by the 7D, the 5D2 would be right in there if not for the noticeably worse pattern banding. The 50D is getting a little worse, but again basically the same aside for the worse pattern banding as with the 5D2. The 20D was far enough behind to be realistically noticeable in usage.
At the print or equally re-scaled image view the 7D should have the best DR since it almost matches the 5D2 but has less pattern banding; next are probably the 5D2 and 40D, the 40D less pattern banding maybe makes up for the 1/3+ stop worse measured difference ; then follows the 50D about 1/3+ stop behind in measured from the 40D but with worse pattern banding and then the 20D noticeably farther behind finishes it off.
The 5D2 should have noticeably better SNR measurements at 18% than the APS-C cams at all ISO. it is possible the 7D might have a tiny bit better and the 20D a tiny bit worse SNR at 18%, after normalization, than the other APS-C cams. Although this is just guessing based on sensor size and mentioned technology.
MAIN POINT:
Does not appear to be anything at all to worry about with the 7D DR compared to the older, lower MP cameras from Canon, it measures 1/3+ stop better at the print level and with less banding than the 50D, yeah no worries at all.
Since it has better microlenses and photodiodes one would imagine that it can't do worse for SNR than the other APS-C cams either at print level.
Despite all the fussing it seems quite likely, although this is tentative, to have the best IQ, even ignoring MP advantage, of any Canon APS-C camera yet, even if the improvement may in many cases be not wildly noticeable other than when pulling very deep shadows at low ISO or in areas of very low light at high ISO.
I.E. don't worry about it one way or the other, other than you should have less banding issues. Main thing to see is if the AF actually does much better or not.
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