SMC Pentax 15mm f/3.5 (Pentax and Pentax-A) - Sample Images
Info and Reviews:
The older SMC Takumar 15mm f/3.5 are optically identical but has M42 mount.
However a few of the earlier Pentax 15mm was made with an Aspherical Element but was quickly taken out of production by Pentax.
Pentax: 1975 - 1984
Pentax-A: 1984 - 2004
Optical design: 13 elements in 12 groups
Lens mount: Pentax K
Covers: Full-frame (24×36mm)
More info / Review: