Is this fungus?

Today I noticed my SW 90mm Fujinon doesn't look the way it used to:

 

<p><a href="http://www.mikesisk.com/photos/fungus-large.jpg"><img src="http://www.mikesisk.com/photos/fungus.jpg" width="375" height="301" border="1" alt="Fuji 90mm" /></a></p>

 

<p>Now, I've never seen lens fugus before--for the past three years I've lived in New Hampshire but before that I was in Southern California and fungus just wasn't something to worry about. But it is a little more humid here in the East in our un-airconditioned house.</p>

 

<p>So, is this lens fungus? If so, what can I do about it? Is it worth trying to fix or is now a good time to replace it with a Super-Angulon or perhaps an SWD?

I can't quite tell from the picture. It looks more like separation of the paint on the edges of the lens elements, but that may be an illusion. Here are some good pictures of what lens fungus looks like along with a discussion of what to do about it:

 

http://www.chem.helsinki.fi/~toomas/photo/fungus/

David, you always have a good answer or input for these questions. I looked a the site you recommended and found out just what I needed to know about cleaning fungus. LF is a blessing in this regard. Most lenses I've seen are easily disassembled for cleaning. Not so for MF and SF.

I don't think it's a fungus - it's too concentrical and regular for a living fungus.

If your talking about those little areas in the black that looks like paint flaking, my 90mm Fujinon is the same way. The strange thing is the little silver spots only show up in winter...in the summer, the black looks like new again. Pretty strange I guess but it doesn't effect picture quality.

It really just looks like the glue is coming unglued... Send it off to Steve Grimes

to get it back like new!

Mike: This doesn't look like fungus, it looks like a Japanese strain of Schneideritis -- discoloration or flaking of the black paint inside the lens. I'd expect this to have absolutely zero effect on lens performance.

If you're talking about the little silvery white flecks around the outside of the lens, then it's not fungus or 'glue coming unglued' at all.<br>As nearly everyone else has said, it's simply the black anti-reflection paint coming unstuck from the outside of the lens elements. It's a common problem with LF lenses.<p>I've found that black 'magic marker' waterproof felt pens are a good way to touch up shedding AR paint.<br>I don't know why lens makers don't use a similar material right from the outset, since it seems to have better adhesion, and is far more robust than the brittle paint they normally use.

Mike: To put your problem in perspective, see how bad it can get by looking at this one: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3004437305&category=30076

 

Again, the lens is probably just fine. This isn't fungus.

Thanks all!

 

I did a search before posting and couldn't find a picture that showed exactly what I had--it seemed resonable to me that fungus would start at the edges and work inward. But, y'all are right--this isn't fungus.

 

Darn, and I thought I had a good excuse for another wide-angle lens...

Just a detail Mike - a "reasonable" start for a fungus is where there is the most humidity for it in the lens. The micro-climate in a lens is quite an interesting phenomenon. Usually it starts where there is the biggest air pocket, away from metal parts or where there is an opening for the air to get in and out.