An Internet Surfer sent me some dark frames from a Canon 5DM2, so I have added
those. This is a full-frame camera with a much larger sensor and therefore
not exactly a fair comparision to the crop format 50D & 7D. However,
the Canon 7D compares well to it, but size matters when it comes to
imaging sensors, and the 5DM2 is still the low noise champ.
P.S. I first used Photoshop Equalize, but that didn't provide a similar comparision. One could also use Threshold, but pushing 6 stops seems to provide an interesting comparision of not only noise levels, but how dynamic range suffers at higher ISO's. Photoshop CS4 was used to process the photos - note that ACR5.5 only has a Beta profile for the 7D. DPP was version 3.7.
This is a brand new 7D and there is negligable dust on the sensor ... which would not have any bearing anyway.
Yes, I'm a bit of a gearhead ... on a related note, here's a
High ISO comparison of the Canon 7D and the 50D
Also, the Canon 50D can shoot fine pictures and did an excellent job in Antarctica and Falklands & South Georgia Islands.
I welcome any comments/suggestion on all this - back to the main Canon 7D versus 50D page