Originally posted by aurele nop ! The AF adaptater won't transform a MF lense into an AF lense. It will only maintain it if the lense is AF already.
it mount only thanks to the K mount which is the same for decade. But that's all.
AF lense have some electronics / mecanichs which allow the AF. MF lense doesn't have it, so it's not physically possible to miraculously transform it into AF lense.
That's pure nonsense, why don't you read the Pentax 1.7x AF adapter manual? Or the relevant section in this forums' database? And please don't answer questions if you have no idea what you are talking about.
The Pentax 1.7x AF adapter was designed by Pentax to allow auto focus with AF cameras with manual focus Pentax lenses. The manual focus lens is pre-focussed (to infinity in most cases or to circa the required distance) and the AF system of the camera meters and focusses the optics of the adapter, and miraculously, the manual focus lens was focussed automatically. The adapter, of course, does not change the lens attached physically, but it does the auto focussing job for the old lens. Again, that's what it was designed for! Pentax states in manual and lens catalogues that this is the main purpose of this adapter, the teleconverter function is a collateral issue and Pentax does not recommend it for close-up work.
Pentax introduced this adapter with the SF1/SFX camera line for exactly one purpose: achieve autofocus with the manual focus K, M and A lenses.
So, back to the question: anyone else with a little bit more of a background, please?