Minolta's circular fisheye — the MC Fish-eye Rokkor 7.5mm f/4, a rare 180-degree specialist.
The Minolta MC Fish-eye Rokkor 7.5mm f/4 is a circular fisheye manual-focus lens for Minolta reflex cameras from the MC generation of the early 1970s. The Fish-eye designation and very short 7.5mm focal length mark it as a circular fisheye, projecting a full 180-degree circular image within the frame rather than filling it.
This is a manual-focus circular fisheye with a 7.5mm focal length and a maximum aperture of f/4, from the meter-coupled MC series. Only the focal length and aperture are stated as verified; other construction figures for this specialist lens are not confirmed here and are omitted. Fisheyes of this type typically include built-in filters behind the front element.
As a circular fisheye it captures an extremely wide 180-degree field rendered as a round image, used for creative wide effects, scientific and technical work, and dramatic architectural or landscape compositions. The strong curvilinear distortion is inherent to the design and is exploited deliberately rather than corrected.
On the used market this is a rare and specialist MC fisheye Rokkor sought by collectors. Given its exposed, bulbous front element, inspect carefully for scratches, haze, fungus and separation, and confirm the aperture and focus operate smoothly. Check that any built-in filter turret works, and note that conventional screw-in filters cannot be fitted to the front.