Balsam separation?

I have purchased a K15mm f3.5. The lens was marked with "severe balsam problem" and priced extremely low. My optimistic hope was that the shop could have been mistaken, that the problem was light fungus, oil or dirt inside the lens. When looking into the lens there is a perfect circlular pattern with "something", and test photos show heavy vignetting wide open and fully stopped down. Is it possible for any of you to diagnose the lens based on the images below? If it indeed is balsam separation, are there workshops that can fix it?

The lens is otherwise in mint condition, and is worth having anyway

I am grateful for any help!

Regards
Bjørn

[IMG]http://i812.photobucket.com/albums/zz50/bjolester/K15.jpg[/IMG]

f5.6
[IMG]http://i812.photobucket.com/albums/zz50/bjolester/K15_f56.jpg[/IMG]

f22
[IMG]http://i812.photobucket.com/albums/zz50/bjolester/K15_f22.jpg[/IMG]

Thanks Algi, I have sent them an e-mail!



I have attempted DIY on some lenses, and without exception I have done more damage than repair...

That is a creative idea, I will for now definitely experiment with some special effects shots!

Thank you all for your help!

Balsam was used ages ago to join two lens elements. It has a refractive index same as glass so was very popular then. But aging affects the glue and separation starts from the lens periphery. This will show up as flare and blur around the edges.
I had a Zeiss binocular with this problem. Just soaked the lens in alcohol for a week and pried the two lenses apart. Removed the balsam coating by gently scraping it with my nails. Cleaned the surfaces with alcohol. Put the lenses together without any gluing and and assembled it back. Worked fine.
Did not notice any perceptible difference except for some slight color fringing between the two eye pieces.

Here is the cheapest source for a possible repair. Do tell them to apply multi coating too. He did an excellent job for of re-coating an old Rolleiflex f2.8 Planar lens. The only condition is you send him the glass and NOT the lens, since he is a manufacturer of optical glass and not a repairer of lenses:-
Mr. Mukul Garg
http://www.universaloptics.in/ [email protected]
UNIVERSAL OPTICS.
D-1, INDUSTRIAL ESTATE.
ROORKEE - 247667.
(UTTARAKHAND)
INDIA

Here is a guy in the US. But be prepared to pay 4-times as much:-
Focal Point Inc.
303-665-6640
[email protected]
300 Center Drive
Suite G-177
Superior, CO 80027

Check out some of the old Russian Federation countries too. Cheap and very good.

Yup. Top lens in most microscope eyepieces is a cemented doublet and I've seen it separate countless times. Schools generally aren't in a position to keep buying eyepieces and so it's clean and rebuild dry. I've done the odd one with immersion oil too, no colour fringing that way.

/but I wouldn't try an oil film inside a camera lens, too much chance of it making it's way into the diaphragm...

I do not know if this repairer does the sort of repair you need, Bjolester but it may be useful in case you need it.

http://www.ajjohnstone.co.uk/

Dave