Asahi Fish-Eye Takumar 6x7 35mm f4.5  type_Collectible this lens can also be

this lens can also be used on a full frame camera

and a pretty easy to handle form factor

It includes a lens board with a 32mm hole (slightly smaller than a Copal 0)

locking in place with thumbscrews

Asahi Fish-Eye Takumar 6x7 35mm f4.5 &nbsptype_Collectible this lens can also beThe Asahi Fish Eye Takumar 6x7 35mm f4. 5 is a true fisheye lens for the Pentax 67 medium format SLR camera. Medium format fisheye lenses are not exactly common, and this is a nice one: it's a "full frame" optic, so it covers the entire 6x7 area without circular vignetting, and it has a set of built in contrast filters for black & white shooting. Smooth focusing, clean diaphragm. A cool lens.