Originally posted by ckiang
Well, actually, whereas Nikon still managed to maintain a high level of backwards compability in their body/lenses, Canon and Minolta chose to develop a completely new range of lenses for their SLR systems.
A large number of Nikon lenses can be used on almost any body. E.g., you can use say, an AF 80-200mm f2.8D ED on a Nikon FE (1978). Now, try using a Canon EF 70-200mm f2.8L IS USM on a Canon AE-1 or even the T90.
The advantages and disadvantages of moving on/sticking to a certain level of backward compatibility has been beaten to dead in many many many debates in so many forums, mailing lists and newgroups that I've lost count.
The simple end conclusion varies
according to the individuals' needs. Nikon had a large following of people owning fully manual cameras while both Canon and Minolta had a smaller portion of the pie by comparison. So for both Canon and Minolta, electing to move on to a mount that better served the needs of future, more advanced bodies was probably a wiser decision on their part. For all parties, it was a marketing decision, period. There is no satisfying everyone at the same time, so while it's great that you can use your AF 80-200mm f2.8D ED on your Nikon FE (in full manual obviously), but I don't have a non EOS type Canon body so why on earth do I care if it works with a T90 or AE-1 ?
As to the confusion of the lenses available for Nikon, its probably due to the fact that there are lenses in the Nikon stable that aren't compatible with every single Nikon camera. So for people not in the "know", its dead confusing to have to second-guess which lens works with what. (Although, sticking to the latest lens with the latest bodies probably gives the least headache.)
For example, my colleague has been complaining to me that he can't use this lens, that lens (don't ask me which ones, I've no idea either) with his FM10.
In the case of Canon, the FD lenses aren't compatible with the EF mounts (at least not unless you have an adapter) and thus the EOS range of cameras only has the entire range of EF lenses to contend with, so no compatibility issues to think about here.