Cleaning lensesgreenspun.com : LUSENET : Large format photography : One Thread
lenses that have fungus or other non clarity.How does one clean?
-- James Tremills (firstname.lastname@example.org), November 19, 2000
James: If the lens is an old clunker, you can probably do it yourself if you do it carefully. You can make or buy the tools for removing retaining rings, but there is room to screw up the lens. For a good lens, I would recommend professional cleaning. A professional lens repairman can recenter the lens elements, which is most important for maximum sharpness. Some of the older lenses were built by turning a lip over the elements, making it almost impossible for an amateur to remove the elements without destroying the lens. For cleaning the older junkers, glass cleaner and good quality alcohol will work.
-- Doug Paramore (email@example.com), November 19, 2000.
I'm offering this on an 'entirely own risk' basis, I take no responsibility for the outcome.
If it's definitely fungus that's in the lens, and it has a good hold, then it'll almost certainly return unless you take drastic action. If the glass hasn't been etched by the fungus, then remove the element from the lens barrel entirely, if possible. Physically remove the fungus with a lens tissue, and treat the glass with a 50% solution of domestic bleach, Sodium Hypochlorate. Then dry and polish the glass as usual, and re-assemble, using a blower brush to keep dust away until the lens is back together.
I've used this treatment on a 2nd hand lens that had a slight fungal attack when I bought it. After the 3rd return of the fungus I decided it was time to get drastic, and treated the lens as above. This was about 10 years ago now. The lens is still clear, and has suffered no long term damage.
If the fungal attack is quite mild, then you might be able to dissipate it with UV. Try putting the lens under a tanning lamp for a few hours. (You could use strong sunlight, but the heat might affect any lubrication in the mount or shutter.)
-- Pete Andrews (firstname.lastname@example.org), November 20, 2000.
The solution of my choice is Windex, esp. the clear (non-blue) variety. Use wads/balls of cotton wool.
Finish up with warm breath, microfibre cloth, and a can of air. I have done this to more than one old lens which had either fungus or haze. Just fixed up a Nikon Series E 75-150 lens this way (that had fungus).
The usual challenge is to keep your work environment as clean as possible and realise that you may not be able to get out all the dust once you reassemble the lens groups.
Watch out for very soft coatings.
To unscrew the lens retaining rings, use a friction tool - e.g., bottle caps on a piece of rubber cut from dishwashing glove.
You may or may not be able to clean up the mess in your lens entirely.
-- K H Tan (email@example.com), November 20, 2000.
I believe it's ammonia that's suggested for removing fungus. And generic glass cleaner from Wal-mart has ammonia and has worked fine to remove any fungus that I've encountered. I assume the Windex is about the same. Look for ammonia.
-- John H. Henderson (firstname.lastname@example.org), November 20, 2000.
What about the cleaning of haze elements specifically? I used analytical-grade pure ethonal but failed to get rid of the haze surface. Thanks for any suggestion!
-- Dongyun Hao (email@example.com), December 04, 2000.