Originally posted by VoiceOfReason Why not do it like the AF adapter Pentax had. You would refocus your lens, and then the adapter would then fine tune it and get it in focus, kinda like the 1.7 AF teleconverter does. This would be awesome for MF lenses too.
Think this requires magnification optics in the adapter. The Q usually doesn't need more magnification with adapted lenses and it definetly doesn't need a smaller effective aperture. Diffraction is always a consideration with adapted lenses on a Q. Even the Pentax DA*300 performs best at f5.6. Add the 1.7X of the original K mount teleconverter and the aperture is over f9 on the 300. Sharpness will suffer. Would be neat if it worked.
I would give up AF on manual focus lenses, and screw drive AF lenses, to get in motor lenses to AF on a Q. This should be possible fairly easily. Don't know if the AF programing in Q lenses works the same as Kfa mount. If not, some electronics would be required in the adapter to translate.
thanks
barondla