The "register" distances are problematic. Sony Alpha has a 44.6mm register distance (distance from camera mount surface to sensor plane) and Canon EOS has 44mm. Canon FD has an even shorter 42mm register distance.
In order to use a lens from system "C" on system "A", the register distance for system "C" must be larger, to allow for an adapter between the "A" camera and the "C" lens. As you can see, this is not possible. More accurately, it is possible, but with limitations:
- With a mechanical adapter, but without the ability to focus to infinity
- With an optical+mechanical adapter, but with some image degradation
In general, it's not possible to adapt Canon lenses to non-Canon SLRs because the Canon bodies are among the narrowest on the market. This situation also enables the Canon bodies able to accept a wider range of non-Canon lenses than almost all other brands. Canon EOS bodes can accommodate Nikon, most M42, Leica M, among others. Oddly, Canon EOS bodies (44mm distance) cannot take Canon FD lenses (42mm distance)! |
