Originally posted by RobA_Oz The funny thing is that Voigtlander lenses were only made for Nikon and Pentax mount for a long time. It was only just before they gave up making Pentax-mount versions that they started making Canon-mount ones. I can't help wondering what the story was there, because the market for Canon-mount lenses was always going to be bigger than either of the other two versions.
I have an SL58/1.4, and the pictures it provides are noticeably different to other lenses in this focal length range (mostly the strength of the blues, I think), but nonetheless appealing, to me. Although I now also have a very nice A50/1.2, I'm reluctant to pass on the Voigtlander because of that difference.
manual K mount lens is no longer subject to copyright control (later A and AF versions are) same with the nikons they made
I'm not sure if the basic EF Mount is Public domain yet, but maybe they just reverse engineered it like everyone else (simpler to since no need to engineer af controls)
Cosina also made a K mount SLR or 2 fully manual (still may actually)
I think Cosina is adapting their business model to more modern realities now (when they started with K mount Pentax had much bigger share and requirements are very similar to a Nikon Manual focus (you can actually make the nikon fit easily with no mods on a pentax body but a small mod will help it lock)