From what I know of the used lens market:
Do not get the Leica M adapter, most wide lenses are in the range of 2X the camera.
Do not choose Nikon, the F mount is still a current working system in digital, this keeps prices high.
Pentax K has much the same issue although not as severe, because the older Pentax are digital adaptable.
So, that really leaves Canon, M42, and Cine.
Canon FD lenses are cheap, and at the time, ( like now ) they had to be competitive with Nikon. I'm a Nikon shooter, so I don't know the full history, but I think right around the time of mature in body auto focus and in camera F shop change, canon made changes to their mount, this has effectively orphaned the FD lenses on the New digital bodies, they work, but just like they will work on the G1, they take an adapter, and AF confirmation is via the focusing screen. ( I think some canon FD/ Canon do have a chip? ) Big pool, cheap lenses, good quality, + third party lenses. The mount runs into the 80's ( I think )
M 42 is a much more mixed bag, it's an older open format, and there are tons of Russian lenses floating aorund in this mount. The quality can be spotty in the FSU lenses.
Cine is strictly experimental. I have 4 lenses, and 3 do not work on the adapter, and even if they did, 2 are really cheap CTV lenses with three aperture blades. The 3rd is way too big for the adapter, ( my bad, should have asked ), and the 4th, a Kodak is a gem, but it does not cover the full image sensor. I have three more on the way ..... I'm a glutton for punishment. Overall, I'm running about $40 average cost on the lenses, so while not expensive, I would have been much better off sticking with a canon FD for absolute economy, but the cine experience has been fun.
Dave
