Fungus in a 1960s Yashica rangefinder, gone after 3 days in direct sun

I picked up a beat-up Yashica Electro 35 at an estate sale in Portland for $20. The lens had that classic spiderweb fungus pattern and I figured it was a parts camera. Out of laziness I left it on my workbench facing a south window for 3 days while I dealt with a stuck shutter on a Canon FTb. When I finally got around to cleaning it, the fungus was basically bleached out and the haze was mostly gone. The coating looked fine too, no separation. I read about UV killing fungus but always assumed it needed a dedicated lamp or several weeks. This was just casual sunlight through glass, maybe 6 hours a day. Took the lens apart anyway and wiped the element with alcohol, but there was almost nothing left to clean. Has anyone else had luck with just ambient sunlight on older glass, or did I get lucky with a mild case?

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jordancoleman15d ago

Thats a nice win, $20 is already a steal for one of those even if the lens was toast. I had a similar thing happen with an old Minolta I forgot on the dash of my truck for a week, the haze did back off some but not as clean as yours sounds. Sunlight through glass can do more than people give it credit for, especially if it hits the glass straight on for hours. Probably the mild case did most of the work, but I'd take that luck any day.