My Nikon FM2 jumps from 1/60 to 1/125 to 1/250 and so on — what’s the story behind those odd steps? Is this just old clockwork timing, or is there a simpler reason those numbers stuck?
They’re just the base‑2 exposure steps — ‘double the speed, halve the light’ — so 1/125 and 1/250 are rounded stand-ins for 1/128 and 1/256, not a clockwork quirk (quick read: Shutter speed - Wikipedia). My practical tip: think in stops and ignore the printed rounding, which makes mental math and bracketing dead simple on the FM2. Are you seeing frame-to-frame shifts or just curious about the numbering?