Here’s a piece of advice that is sure to be controversial—the 21MP Canon EOS 1Ds Mark III is no match on a per-pixel quality basis to the 10.1MP Canon EOS 1D Mark III, which I raved about throughout 2007. That’s a pity; scaling up the 1DM3 sensor to full frame would have yielded 17MP, ample resolution. Instead, Canon chose an inferior sensor technology at 21MP.
Better yet, if you want terrific color and low noise without the bloated file size of the 1DsM3, get a Nikon D3! I’ll be reporting more on the 1DsM3 in the next few months, but (literally) when I look at the 1DsM3 and the Nikon D3 sitting on my desk, my hand always reaches for the D3 first when heading out for a shoot. But perhaps the 1DsM3 will prove itself in Death Valley when I go in 7-10 days (other work demands have delayed my trip). On the negative side, its disappointing that I can’t shoot lenses like the Leica 180/2.8 APO (see review) on the D3—Nikon’s flange focal offset distance precludes lens adapters, whereas Canon’s does not.
Bottom line: consider very carefully whether megapixels alone “floats your boat”. There are so many other reasons to choose a camera. The same principle applies to lenses, and of course technique and tripods matter too.