The 'shim stack' comment that changed my lens alignment approach

Tbh, I used to just brute force collimation with whatever shims I had on hand, usually brass, and hope for the best. About 2 weeks ago a guy in a shop in Portland watched me do a Canon 50mm f/1.4 and said 'you're stacking tolerance errors, not fixing them.' He pointed out my shims were all different thicknesses and I had a burr on the helicoid. Switched to measuring each shim with a micrometer and using one single thickness piece per stage. It took me an extra 45 minutes on the first job, but the infinity focus was spot on. I still don't love doing it, but the results are way more consistent. Anyone else had a similar wake-up call about how they stack lens elements?

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green.jenny3d ago

Micrometer changed everything for me, used to just eyeball it too.

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