Simple query really...anyone done shoots with both bodies and have an opinion on how they perform up to ISO 200...which is where I do my studio shoots with a 40D, a 1V with HP5 shot and deved at 200 ISO..My max print size is A3 plus and both the 40D images and the scanned 35mm images are pretty good at that size....
I moved up from my 40D to a 5D2, but eventually got a 7D as a backup.
I think that the low ISO on th 40D is cleaner at 100% pixel-peeping, of course the 7D has more pixels.
I don't think the 7D's low ISO noise would be a problem at A3 print size, unless you have severely underexposed the image.
You will also get a noticeable increase in detail with the 7D.
At A3+ I doubt you will see a big difference. If any difference at all. Especially if you shoot people in the studio. Of course the 7D is full of features and is the better camera, but for studio work I don't see the relevance.
At A3 there should be a difference in the fine details, like clothing textures and small type on product packaging. The difference may not be a big deal for most, but I can see the difference. I think that the ability to crop more has it's merits as well.
Yeah my test was hardly scientific, and I wish I would've done multiple exposures and checked focusing. You know what I mean? I dicked it up, because what I did was like focus/recomp on the tripod. It was awhile ago, but if I had access to a 40d I'd do it again with a prime (at that point I didn't own a prime; just zooms).
They were processed the same way, but flash was ettl I believe.
Also for what it's worth, my 7d and old 40d produce sharp captures.
