Right - interchangeable lenses are not adapter ring clip ons - example - the Canon EOS D30 and D60 accept all standard Canon EOS lenses. Basically you buy the body and add lenses as you can. There is one factor in that - due to the difference in the 35mm film size and the digital sensor array, there is a 1.6 multiplication factor applie to all Canon lenses for these prosumer cameras. Example, a 50mm f/1.8 lens would be equivalent to an 80 mm lens in terms of what is on the sensor array. Once you cross that threshhold, you can use any make of lens that is designed for the EOS mounting system - Sigma, Tamron, Canon, Vivitar, and others.