Pentax's 67-era medium-format fisheye — the SMC Pentax 67 35mm f/4.5 for the 6x7 frame.
The SMC Pentax 67 35mm f/4.5 Fisheye is the later-branded version of Pentax's medium-format fisheye for the 6x7 system. It carries the SMC Pentax 67 name used from around 1989, the third naming generation of the line after the Takumar 6x7 and SMC Pentax 6x7 labels, and continued to serve the same full fisheye role on the 6x7 frame.
This is a manual-focus lens for the Pentax 67 bayonet, covering the 6x7 cm negative. Maximum aperture is f/4.5 at a fixed 35mm focal length. It produces a fisheye projection over the large frame, and the Super Multi Coating denoted by the SMC prefix helps control flare and ghosting when strong light sources fall within the very wide angle of view.
As a fisheye the lens curves lines that fall away from the centre, which shooters exploit for interiors, wide landscapes and creative distortion on the big negative. The short focal length gives deep depth of field, making focus forgiving, while a moderate stop-down tightens detail out toward the edges of the wide image circle.
On the used market this 67-branded fisheye is a specialist item bought by Pentax 6x7 and 67 owners. Inspect the exposed front glass for cleaning marks and haze, check for fungus given its age, and confirm the aperture ring clicks cleanly with dry blades. It adapts to mirrorless bodies through a Pentax 67 mount adapter for those who want the projection on digital.