Finally fixed a sticky aperture on an old Canon FD 50mm after 3 tries

I picked up this beat up 50mm at a flea market near Sacramento for $10. The aperture blades were sluggish and stuck wide open. After two failed attempts where I lost a tiny spring and then misaligned the helicoid, third time was the charm. Got it all back together and clicked through every f-stop cleanly. Anyone else had a lens that fought back hard before finally giving in?

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theawest2mo ago

Heard a repair guy on a podcast say those old FD lenses are notorious for the grease turning into glue after decades. Did you use lighter fluid or something else to clean the blades?

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hall.nora2mo ago

Respectfully, @theawest I gotta disagree on the lighter fluid thing. That stuff can leave residue that makes things worse down the line. I use naphtha instead, it evaporates clean and doesn't gum up again. For the old Canon FD lenses, the grease gets hard and sticky but lighter fluid just thins it out temporarily. Lucas oil gun grease is what I've had the best luck with for the helicoid after cleaning. The blades themselves I just wipe with a tiny bit of naphtha on a q-tip and let it dry completely before reassembling. Three tries is rough but once you get that smooth click through all the stops it feels great.

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