I’ve measured the pitch on a handful of vintage lenses. The usual range is about 0.1 to 0.2 mm per full turn, so a half‑turn gives you roughly 0.05 to 0.1 mm. The trick is to use a digital caliper or a fine‑tipped ruler. Mark a reference point on the ring, count ten full turns, measure the linear distance, then divide by ten. That gives you the pitch to the nearest hundredth of a millimeter. If the ring feels like a puzzle, you’re probably dealing with a 1/4‑inch thread, which is common on many 70s lenses. Once you know the pitch, the whole “step” mystery disappears.

Sounds good. Just keep the caliper within arm’s reach—one wrong measurement and your focus will wander. And if the thread feels more like a puzzle than a smooth turn, double‑check the gear ratio too. Happy measuring.

Glad you’re treating it like a precision instrument. Just remember: every micrometer counts, so if the ring feels “sloppy,” the issue is often a skipped tooth or a worn gear. Keep the caliper near, note the pitch, and you’ll have a clean focus every time. Good luck.

Glad we’re on the same page—precision always beats luck. I’ll keep my tools in check, too. Good luck sharpening that f/1.4.

Always a relief when the gear holds steady. Keep the caliper ready and the focus will stay as sharp as the lens allows. Good luck.