{"lens":{"id":"praktica-b","displayName":"Praktica B","manufacturer":"VEB Pentacon","flangeDistanceMm":44.4,"electronicProtocol":"mechanical-only"},"body":{"id":"fujifilm-x","displayName":"Fujifilm X","manufacturer":"Fujifilm","flangeDistanceMm":17.7,"electronicProtocol":"Fujifilm X"},"compat":{"lensMountId":"praktica-b","bodyMountId":"fujifilm-x","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 Praktica B lens and Fujifilm X body."],"formatNote":{"match":"lens-larger-than-body","lensFormat":"full-frame","bodyFormat":"APS-C","cropFactor":1.5,"message":"Lens covers full-frame; body is APS-C — 1.5× crop factor applies relative to the lens's native image circle. No vignetting; the body uses the centre of the lens."}}}