Jupiter-12: Rear Element Cleaning + Scratches?

Hi everyone,

 

I posted a while back asking for a rangefinder recommendation and landed on the FED-2. I just picked up a Jupiter-12 from an ebay seller for not too much, and it looks to be in fine shape, save for a few things: there seems to be some smudges/fingerprints on the rear element and a few tiny scratches. How should one go about cleaning this protruding rear element? Is using a blower + wiping with lens tissues okay? Also, how worried should I be about these scratches? They're hard to see, unless in bright light. I've heard that the protruding element is closer to the focal plane, so scratches there could really impact photos (unlike ones on the front element).

 

Thanks in advance!

To clean the lens, use compressed air, then soft brush, then microfiber cleaning cloth moistened with lens cleaner. Rear lens scratches are worse than equivalent front lens defects. Any rear lens defect will be clearly visible when shooting towards the light at small apertures. Point a bright flashlight in the lens and observe resulting image formed on a white piece of paper. If dark fuzzy spots or lines are seen, the lens is degraded.

then microfiber cleaning cloth...

Fresh lens tissues are far less likely to scratch a lens than a microfibre cloth that's been used several times - picking up who knows how much grit in the process.

 

Despite the hype around microfibre cloths, there's no guarantee that one will be any cleaner, or free of grit, than any other bit of old cloth that's equally well-used.