{"lens":{"id":"m42","displayName":"M42 (Pentax / Praktica screw mount)","manufacturer":"Various","flangeDistanceMm":45.46,"electronicProtocol":"mechanical-only"},"body":{"id":"c-mount","displayName":"C-mount","manufacturer":"Various (cine / industrial standard)","flangeDistanceMm":17.526,"electronicProtocol":"mechanical-only"},"compat":{"lensMountId":"m42","bodyMountId":"c-mount","feasibility":"mechanical","af":"n/a","is":"n/a","aperture":"manual-ring","infinityFocus":"yes","adapterExamples":["generic mechanical adapter ring (multiple vendors)"],"caveats":["Mechanical adapter only — no electronic communication between M42 (Pentax / Praktica screw mount) lens and C-mount body."],"formatNote":{"match":"lens-larger-than-body","lensFormat":"full-frame","bodyFormat":"16mm-cine","cropFactor":2.7,"message":"Lens covers full-frame; body is 16mm-cine — 2.7× crop factor applies relative to the lens's native image circle. No vignetting; the body uses the centre of the lens."}}}