Hasselblad's CF-era full-frame fisheye — the Zeiss F-Distagon CF 30mm f/3.5 for the 6x6 V system.
The Carl Zeiss F-Distagon CF 30mm f/3.5 is the full-frame fisheye of the Hasselblad V system in its CF form, the generation that introduced the Prontor CF leaf shutter and the black rubber-ringed barrel. It replaced the earlier C version of the same optic and remained the widest lens available for the 6x6 format, delivering the broadest field of view Hasselblad offered.
This is a manual-focus Hasselblad V lens with an integral leaf shutter, the CF design separating the aperture and shutter controls into independent rings and adding an F setting for use on bodies with a focal-plane shutter. The maximum aperture is f/3.5 and it covers the full 6x6 frame with fisheye projection. Because of the domed front element, filtration was handled by a set of built-in filters chosen on the lens rather than front screw-in glass.
As a fisheye it produces the characteristic curved rendering of lines away from centre and takes in a very wide angle, making it a tool for dramatic interiors, cramped architectural spaces and sweeping landscapes. The effect is pronounced and deliberate, so it is chosen for its look rather than as a standard wide-angle lens. Kept level and centred, it can also be used where a near-straight horizon is wanted across a huge field.
The CF 30mm is uncommon and holds strong used values. Confirm the CF leaf shutter operates smoothly across its speed range and that the C/F selector and PC-style linkage behave. Look for internal haze, fungus and separation, check the built-in filter mechanism, and inspect the exposed front element for scratches. Verify the aperture and focus rings turn evenly and that the blades are oil-free.