I just rented this body for 3 days to shoot low-light, high school gymnasium lighting, with fast, erratic, fast-paced action...called winterguard (indoor colorguard), using only ambient lighting, with no strobes. Therefore, this camera really got put to the test. My review is mainly based on this subject, therefore, the focus of this review is specifically low-light, high-ISO action.
First off, the LCD screen on this body has to be the most annoying thing on the body. Nothing looks in precisely in focus on the screen. The colors look better than the Mark II N on the LCD screen.
I hate how you delete images. It is 180 backwards from the mark II N.
I like where the ISO is placed on the camera. Why didn't they put the same ISO button on the portrait shutter side? Those two shutter areas should mirror each other, IMO.
What happened to the WB button that I like using on the Mark II N?
I heard great things about how much better this camera was vs. the Mark II N for low light action. I have to say that it isn't much better at all. It does a fine job acquiring focus. At a close distance, it seems to struggle tracking. I set everything up like I would have on my Mark II N. I shot both bodies and I used the same 200mm f2.8 lens like I have done many times on the mark II N for this subject.
Image quality, I think the Mark III is cleaner and nice colors. But, I think my Mark II N produces consistently sharper photos.
I also like the feel of the shutter on the mark III. Feels more solid than the Mark II N's.
If I am a Mark II N owner, I would pass on this body until canon comes out with a newer edition.