Pro photographers have an even more difficult choice to face when going with Canon or Nikon thanks to the new Canon EOS 1D Mark IV ($5,000). Like the recently announced Nikon D3s, the Mark IV sports a maximum ISO of 102,400 and HD video recording — in full 1080p, unlike the 720p-limited Nikon — and also packs a 45-point autofocus sensor, dual DIGIC 4 imaging processors!!, a 16.1 megapixel CMOS sensor (not Fullformat), 10 fps shooting, a three-inch LCD, and more…