Bronica's 6x6 fisheye — the leaf-shutter Zenzanon-PS 35mm f/3.5 Fisheye for the SQ system.
The Bronica Zenzanon-PS 35mm f/3.5 Fisheye is an ultra-wide fisheye lens for the Bronica SQ 6x6 medium-format system. It belongs to the later PS generation of Zenzanon optics for the SQ-Ai era and was one of the most specialised lenses in the SQ range. On the square 6x6 frame the 35mm produces a very wide, curvilinear fisheye field of view.
This manual-focus lens uses the Bronica SQ leaf-shutter mount and provides a focal length of 35mm at a maximum aperture of f/3.5. It carries the in-lens Seiko leaf shutter shared across the SQ system, so flash synchronisation is available at all shutter speeds. As a fisheye it renders strong barrel curvature by design; further construction figures are omitted here because they cannot be confirmed from the sources at hand.
The fisheye produces a dramatic wide view with pronounced bending of straight lines toward the frame edges, suited to creative landscape, architectural and interior work and to sky and horizon compositions. It captures an extremely broad angle in a single 6x6 frame. Photographers used it for deliberate distortion effects rather than rectilinear coverage.
On the used market this fisheye is scarce and among the more expensive SQ lenses because of its specialist nature and limited production. Check the leaf shutter fires evenly across speeds and inspect the protruding front element carefully for scratches, as the exposed glass is vulnerable. Look for haze and fungus inside, confirm the aperture is dry, and verify the mount coupling to the body.