The upgrade from any of Canon's APS-C/1.6x bodies to the Canon EOS 1D Mark IV is a big one - and of course, the cost to trade up is reflected in this. Those not needing the fast performance, impressive AI Servo AF and rugged, sealed build of the 1D Mark IV may find the
Canon EOS 5D Mark II to be a better option - especially better from a cost perspective. The 5D II's image quality is at least as good as the 1D IV's (with higher resolution) and the full frame sensor is a big feature for me personally.The upgrade from any of Canon's APS-C/1.6x bodies to the Canon EOS 1D Mark IV is a big one - and of course, the cost to trade up is reflected in this. Those not needing the fast performance, impressive AI Servo AF and rugged, sealed build of the 1D Mark IV may find the
Canon EOS 5D Mark II to be a better option - especially better from a cost perspective. The 5D II's image quality is at least as good as the 1D IV's (with higher resolution) and the full frame sensor is a big feature for me personally.