If you have been waiting for Canon to unleash an update at the top of their DSLR line-up, you might want to get that credit card ready. As the name would suggest, this $4,999 body is a follow up to the 1D Mark III, to which it's almost physically identical. Inside, however, lives a completely new 16.1-megapixel APS-H CMOS sensor. The pixels are actually smaller than they were on the Mark III (5.7 microns down from 7.2), but Canon claims to have actually reduced noise levels. We're certainly glad to hear it, because the expanded ISO range goes from 50 all the way up to the 102,400 mark hit last week by Nikon's D3S.