{"lens":{"id":"m42","displayName":"M42 (Pentax / Praktica screw mount)","manufacturer":"Various","flangeDistanceMm":45.46,"electronicProtocol":"mechanical-only"},"body":{"id":"rf-cine","displayName":"Canon RF (cine)","manufacturer":"Canon","flangeDistanceMm":20,"electronicProtocol":"Canon RF"},"compat":{"lensMountId":"m42","bodyMountId":"rf-cine","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 Canon RF (cine) body."],"formatNote":{"match":"match","lensFormat":"full-frame","bodyFormat":"full-frame","cropFactor":null,"message":"Lens image circle (full-frame) matches body sensor (full-frame) — no crop or vignetting concern."}}}