How sharp is the Canon EOS 1Ds Mark III?

A reader emailed with some extensive questions on the 21MP Canon EOS 1Ds Mark III vs the 12MP Nikon D3. One of those questions was about sharpness. The best lenses are needed for the EOS 1Ds Mark III; its sensor does not “forgive”. In striking comparison, the Nikon D3 is magic with lenses I considered marginal before (eg many older AI-S Nikkors). But the Zeiss ZF 100/2 Makro-Planar offers more performance than even the 1DsM3 needs (see example below).

Below is an example whose actual-pixels crops show the limits of achievable sharpness on the EOS 1DS Mark III (sorry, no comparison with the D3 on this one). You won’t get this kind of extreme detail on the Nikon D3, but you will get other improvements in image rendition, such as color rendition and a “look” that is more transparent and lifelike (my unabashed opinion).

Click to see a larger size and actual pixels crops. (JPEG compression reduces the quality on the full-frame image, but the actual pixels crops are minimally compressed). No special handling or processing used here—DPP with Daylight, Standard, Sharpening=2. Of course, a skilled Photoshop jockey could make many post-processing improvements to this image, but that is not the goal here.

Canon EOS 1Ds Mark III (ISO 50) + Zeiss ZF 100/2 Makro-Planar @ ~f/5.6