They're both crappy; use ISO 25,600 only as needed. Each has nasty banding and any normal person would reject these images, unless of Sasquatch himself, as garbage.
The Canon uses a lot of noise reduction (smearing) to clobber the noise, so it has no more resolution than the D3 at these speeds.
The biggest difference is that the 5D Mark II is also lowering its color saturation to attempt to hide the noise, while the D3 retains much better color.
Why this self-portrait? This is actually a very sneaky test: the fur on my face and eyes lets us see texture to look for the horrid effects of smudging from noise reduction, and the out-of focus wash behind my head lets us see noise at various levels on flat parts of the image. The out-of-focus transition behind my head is very deliberate.
I used the 105mm f/4 Micro-NIKKOR AI from 1980 because it's an ultra sharp lens, especially at the 1:8 reproduction ratio used here, and because it doesn't use floating elements or zoom. Its optical core is locked down solid, so nothing changes as put on different cameras with kludgy adapters. Newer macro lenses and zooms would all change their optical properties with floating elements as the flange focal distance varied slightly with the silly Nikon -> Canon adapter I used.
I left NR and sharpening at defaults. These are the actual images (JPGs) created by each camera. If you prefer to shoot raw, your results will vary all over the map depending on which software you use to anneal the raw files into actual images.
The 5D Mark II was running firmware version 1.0.7.
I support my growing family through this website.
If you find this
as helpful as a book you might have had to buy or a workshop you may
have had to take, feel free to help me continue helping everyone.
If you've gotten your gear through one of my links or helped otherwise, you're family. It's great people like you who allow me to keep adding to this site full-time. Thanks!
If you haven't helped yet, please do, and consider helping me with a gift of $5.00.
The biggest help is to use these links to Adorama, Amazon, B&H, Ritz, and J&R when you get your goodies. It costs you nothing and is a huge help to me. These places have the best prices and service, which is why I've used them since before this website existed. I recommend them all personally.
Thanks for reading!