I have been shooting with the eos 1ds mark3 since 2008/9 (which I've loved) but.. I think I am quite overdue for an upgrade, but to what???
I've heard terrible things about the 1dx, plus it would be a downgrade in megapixels.
So does that just leave me with the 5dmark3? And is that really more of a sidestep than an upgrade? Thoughts? Advice?
Is there a better camera that I just don't know about? Is the nikon d800 worth the switch?
I have read many things across the web that make some pretty sound reasons why the resolution difference between the 5DIII/1DsIII and 1DX are trivial. Some make a linear printed DPI comparison and others factor in noise and how it impacts resolution. Most of what I have read essentially boils down to this: low ISO (~<400) is the only place you will find any minute resolution differences, and it takes pixel peeping to find it. Anywhere else, the 1DX is far superior.
Many sources claim that the 1DsIII is still tops at 100 ISO.
The ergonomics between the 5D series and 1D series are completely different.
Metering between the 5D and 1D series is not the same.
On the surface the 5DIII and 1DX appear to have the same AF system, but they do not.
I know nothing about the Nikon cameras.
The rumored Canon "big megapixel" is still vaporware. When it does come out, I wouldn't be surprised if it is close to $10k USD. Then there is all of the other stuff that goes with it, like ~50Mb RAW files.
If I was in your position, I'd seriously consider renting the 5DIII and 1DX and put each through their paces. Or join CPS and try to get a loaner.