Schneider's enlarger lens — 75mm for darkroom printing, not camera use.
The Schneider Componar-C 75mm f/4 is a darkroom enlarger prime lens from Schneider-Kreuznach's Componar-C series, designed for producing photographic prints from medium format (6×6, 6×4.5cm) negatives in a darkroom enlarger. M39 (enlarger screw thread) mount.
f/4 maximum aperture. 75mm focal length (optimised for medium format negative enlargement). Componar-C flat-field formula. M39 (39mm screw thread) enlarger mount. For darkroom photographic enlargers.
The Componar-C 75mm is optimised for medium format negative-to-paper enlargement in a darkroom. Enlarger lenses are designed for flat-field close-focus reproduction (negative to paper), not for general photography. Can be adapted for macro photography on modern mirrorless cameras using M39-to-mirrorless adapters with extension tubes.
On the used market the Schneider Componar-C 75mm f/4 is a specialty darkroom enlarger lens. Condition checks: glass elements for haze or fungus (darkroom humidity exposure is common), aperture blade condition, M39 thread condition. M39 mount — designed for darkroom enlargers; can be adapted for close-focus macro photography.