With Nikon, you can mount almost every lens they have made on almost every body.
With Canon, because of the flange distance (IIRC), you can mount almost every Nikon lens on a Canon body.
YES, EXACTLY right, o hey tyler. The flange-to-film distance on Canon is LONGER than it is on many other lens mounts; therefore, there is plenty of extra room to build an adapter that will go behind a lens from, say, an M42 screw-thread, or a Nikon F-mount, or a Leica R-mount, or an Olympus O-M mount. Seven different 35mm "system" lenses will easily adapt to Canon EOS, with NO GLASS needed in the lens adapters to achieve full infinity focusing. This means it's finally possible to put some world-class wide-angle lenses on a Canon EOS body; wide-angle lenses have long been a very weak spot for the Canon company. Canon makes very few W-A prime lenses, and many of them are, well, sub-standard compared to what Nikon and Leitz have been making for decades. Canon's wide-angle L-series zooms (16-35/2.8 and the Mark II version of same) are also kind of suspect as well, falling flat on MTF compared to Nikon's older 17-35 AF-S and just being flat-out ass-whipped by the new 14-24 AF-S Nikkor zoom.
I snapped these two images last night on my desk, after dinner.
View attachment 16945The tall,extended lens on the left is an M42 thread-mount Vivitar 55mm f/2.8 1:1 macro; Nikon 24mm f/2.8 Ai-S with CLoser Range Correction flaoting element system on camera; Olympus 28mm ultra-compact f/2.8 wide-angle; Asahi 135mm/3.5 and 200mm f/4 SUpr-Takumars in back; M42 mount Super-Lentar 35mm f/2.8...a $13 garage sale lens that at f/4 to f/10 is about as good as the 24-70mm f/2.8 Canon L zoom...only with lower distortion and higher resolution than the "L"-glass zoom... and in this second desktop snap, we get
View attachment 16946 a more close-in look at the Canon 5D classic body ($700-$800 used) with the Olympus 28mm/2.8 prime ($45, pawnshop), and the Vivitar 1:1 macro racked out to its glorious full extension for 1:1 life-size macro, and the Ashai Super-Takumar pair.