If I recall correctly:
M42 50/1.4 = K 50/1.4
M42 SMC and Super-Multi-Coated lenses had SMC on the external surfaces of the groups of elements. K mount lenses had SMC coating on all elements surfaces.
M 50/1.4 basically similar
The M 1.4 lens was redesigned.
A 50/1.4 = F 50/1.4, and a slightly improved design than the previous
Other "K" lenses that appear to be M42 lenses in k-mount:
15/3.5 (although there are two versions of EACH, one asph and one not)
Yep. Quite a few Takumar were aspherical, but very few K lenses were.
24/3.5?
Same lens.
35/3.5 35/2
Said by Asahi to have been slightly modified. Not notable looking at the lens diagram. Maybe they discarded the yellowing element and played with the composition of other elements to compensate without changing the configuration? Anybody has a yellowing K35/2?
85/1.8
Same optics, but squeezed in a smaller barrel. The only K lens with 52mm filter ring that cannot take the 52-49 step-down ring.
105/2.8 (this design is REALLY old as Pentax glass goes)
1961. The 35/3.5 is an older design though (1959).
135/2.5 135/3.5 200/4?
Same.
400/5.6 500/4.5
1000/8 also.
Apparently NOT 28/3.5, which is odd, as the M42 28/3.5 is a great lens.
Asahi did not rested on their laurels, they made it even better!
It's interesting to me that many of the lenses on this list are now the rare and desirable ones. I've got all of them in M42 and none of them in k-mount.
They will be easier to use on a D body!
Cheers,
Andre
