Some nights, when sleep seems like a bad idea, I drift through ebay looking at old camera lenses, mostly for educational purposes. There was a time in the 1970’s, for instance, where computerized lens design and super-high-tech coatings for the glass became common. Many very good lenses were created, only to be quickly outmoded by the autofocus revolution.
When Canon embraced autofocus, they took the opportunity to redesign their mount, making the hole bigger and farther from the film/sensor. This provided tangible benefits for super-high-performance lenses, but it meant that none of the pre-autofocus lenses were compatible with the new cameras at all.
With a few exceptions that don’t apply to everyday photographers, you can’t shoot old Canon glass on a new Canon body.
Nikon, meanwhile, kept the geometry of its older cameras so that old lenses would still work. Funny thing, though. According to the sources I read late last night, they way Nikon does light metering when one of those old lenses is attached really isn’t very good.
The sweet spot: Old Nikon lenses on a modern Canon body. The adapter costs only a few bucks and you can get a great lens for a song (though it’s a costlier song now that people are catching on). Apparently Tim Burton shot a whole movie (one even I had heard of) that way, with a variety of older Nikon lenses on Canon 1Ds. That has to make the brand snobs squirm a bit.
That Nikkor 50mm f1.2 AiS.C is looking pretty nice right now. Someday…