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07-12-2012, 07:49 PM   #1
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Is this fungus?

Greetings all,

Been lurking here for quite some time & finally coming out from under my rock...

I recently picked up a lens I've been wanting for a while now - a Vivitar 600mm solid cat. Got it from the big auction site and knew from the pics that it was fairly dusty/dirty on the outside. Once cleaned, however, I see this around the edge of the lens.

Near as I can tell, this is on the inside of the front element. I've looked through threads here & on other sites about fungus on lenses, but having never seen it up close & personal I'm still not sure if that's what this is. If it is fungus, anyone have any recommendations for a person or shop that could attempt a cleaning? I've found precious little info on this lens as it is (but apparently still enough to have made me want one! ), let alone a repair manual or instructions on taking it apart.

For now, I'm just leaving the lens exposed to some sunlight as that seems to be a common solution for keeping it from getting any worse. It doesn't seem to affect any pics that I've taken (yet), but I suppose that's due to the cropped APC-sized sensor in my K10d as much as anything.

Any help/suggestions/recommendations would be most appreciated!


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07-12-2012, 09:35 PM   #2
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It could be but it is atypical. Generally the threads are more random in direction. That looks more like scratches, but I have no idea how anything could get scratched like that. But then I've never seen fungus on a mirror lens before.

Don't worry overmuch about it spreading, it is dead and not going to restart growing. Fungus requires warmth, moisture and food to grow, take away any of those and it dies. The spores that cause it are in the air we breathe and in and on all of your equipment. Provide an environment it can grow in and it grows. So keep your gear dry and in a low humidity storage. Never put anything in a dark damp basement.

Out on the edge like that I doubt it will affect the IQ in any visible way so unless you can see an issue in a photograph I would not worry about it.
07-12-2012, 11:37 PM   #3
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If it's on the mirror it could be separation of the mirroring from the glass due to damp.
07-13-2012, 12:03 AM   #4
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I vote for fungus.

07-13-2012, 02:14 AM   #5
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It looks like fungus unfortunately.
07-13-2012, 03:47 AM   #6
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If thats fungus, they're more organized than me. They're on a straight path!
Could be fungus, i don't really know.
07-13-2012, 06:28 PM   #7
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Looks like fungus to me. In our lab, we see that growth when the fungus is growing from a nutrient poor area into an area richer in nutrients. Not sayin' that's what's happening here, just that I've seen fungus grow this way pretty frequently.
07-14-2012, 04:47 AM   #8
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I say fungus too. It usually looks more like cobwebs, but that's not carved in stone. I recently had to send back a Lentar 300 that had fungus in the rear lens, when I removed and tried to clean it I got the fungus but found it had etched the lens, and it looked more like a fingerprint smudge than anything else. Tiny roundish spots in fairly straight, parallel lines.

Oh hell, here's a picture, I can't describe it well enough. The scratches are on the other side of the lens and from someone's botched cleaning attempt before I got it. Probably from a grubby t-shitrt...

I've seen other pictures, and have a Pentax 50mm with fungus that looks more like cobwebs or in some cases looks like a drop of oil in a pan of water. Fungus grows according to its own pattern, which depends on which of thousands of varieties of fungus it happens to be. In your yard or in the woods it looks like mushrooms...on a slice of bread it grows in round blue or black spots...

Anyway, in the picture above, that's the etching it left behind. I neglected to take a "before" picture, it was white and just looked like a foggy spot. SO I thought it was a smudge from a previous cleaning attempt, and when I removed the lens, (quite easy to do, just unscrew the rear barrel section) I found out it was on the inside and cleaned off pretty easy with acetone. But the etching you see above remained. I would have never guessed fungus...but the only other thing I know of that will etch lens glass is fingerprints, and this is not curled enough to be a fingerprint, it's fairly straight lines. You don't have any lines that straight in your fingerprints...not that long anyway. That lens is 1 1/4 inch in diameter and it goes all the way across. The only place a person's hand could do that would be across the palm, in a couple of places.

I think the lens in question has fungus. If you can remove the front element, it's probably just one lens, it would require removing the front retainer ring. That's the ring with the lens brand and focal length printed on it. Since they usually have no slots for a spanner tool, it's not easy and you risk gouging it, but it can be removed with either a special tool or something with a point to turn it with. I wouldn't recommend trying it if you aren't familiar with the procedures required and don't have the right tools.

07-17-2012, 07:25 PM   #9
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Thanks everyone for your input! The marks don't appear anywhere except the outer edge, so I think I can live with it. I took the lens to a local camera shop, and the owner is putting me in contact with the person that does his lens repair work. He might be able to do as Pete says and remove the front retainer ring to take a look.

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