> personally, I found the KA version less reliable, because often the > contacts were just a tiny bit off and didn't make proper contact. It > sure freaked me out when suddently I couldn't take a photo. I threw it > out afterwards. Having to rotate the lens a bit on/off to be able to > get a photograph is not my idea of good design...
This is exactly the same as my experience with the Ka-mount version of the Adaptall-2 mount - a little "flaky". And "flaky" does not make for dependability. However, I do know that others have said they've never had a problem. > The plain old K is the best, both mechanically and without exposure > quirks because of bad contacts. I don't have too many Tamron lenses, but the ones I do have I really like; however, I use them only with "plain old K" Adaptall-2 mounts. By the way, my post here is not any sort of a "scathing condemnation" of Adaptall-2 mounts - I think that the Adaptall-2 system is an example of some really very clever engineering. However, the era of "program" bodies back in the early 1980's did impose a complication on the mount system that, in my opinion, has never been totally successfully coped with (at least with the Ka version of the mount). (YMMV) Fred