SMC Pentax-M 1:3.5 135mm with fungus


samson51

Link Posted 26/01/2013 - 23:04
All cleaned now .Three screws found under focusing rubber.

screwdriver

Link Posted 27/01/2013 - 02:20
Clearing the fungi, unfortunately, is not the end of the problem, most fungi of a type that grows on glass secrete Hydrofluoric acid which eats into the glass, the glass becomes food for the fungi.

So even though you have removed the fungus the lens will still be etched glass where the fungi once was and the lens will tend to flare.

I have heard of, but never tried, using the resin that car windscreen repairers use.

You can have the lens reground and polished or renew the lens from a scrap lens that has damage elsewhere, but that gets expensive.

Just avoid any lens that has fungi, unless the lens is rare and has real value, fungi is normally death to a lens.

UV kills fungi, sometimes all you need to do is put the lens in bright sunlight for a week or two if the infection is slight.
Chris

xyzmurali

Link Posted 07/11/2017 - 06:19
Hi,
I recently got this lens and am trying to clean the fungus. I was able to remove one of the front element glass and clean it. I was not able to find way to reach other elements from front nor I was able to remove the screws from back. Is there a way to reach and clean all elements from front and clean the lens without opening the screws at back. Any help is appreciated. Thanks

Regards,
Murali

pschlute

Link Posted 07/11/2017 - 11:31
No that is not possible. Where is the fungus ? front or rear elements ?

Take some pictures of the disassembly so far and we should be able to advise on how to remove the second and third front element.

http://kmp.pentaxians.eu/wp-content/uploads/bojidar/lenses/primes/_optics/135f3....
Peter



My Flickr page
Last Edited by pschlute on 07/11/2017 - 11:34
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