If you have an interest in how the latest in high-end digital SLRs are designed, you might want to read Canon’s white papers on the 21.1-megapixel Canon EOS 1Ds Mark III and the EOS 40D. There is much interesting material. Why doesn’t Nikon provide such white papers?
The discussion of microlenses (page 11) is particularly interesting, along with the claim that the 1Ds Mark III will offer noise as low as that of the 16.7-megapixel 1Ds Mark II, in spite of the 25% larger pixels of its predecessor. Does this mean that the issue of diffraction might be no worse in spite of the pixel size difference (since the photo diode size remains the same)? That remains to be seen in real pictures. Please email if you have insights into that topic and I will share it here in this blog.