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05-18-2011, 08:14 PM   #1
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So this is fungus right? Time for the trash bin?

I have this Mamiya Sekor 55/1.8 that I got from my grandfather. It sat in a closet for like 20 years and the other day I was at my dad's house and I found it. I realized it was M42 screwmount (there's an old ratty body to go with it), and I wanted to use the 55 on my ME, because it's the chrome-accented version, and it would look oh-so-sexy. However, it's got this blemish on the rear element:



So that's fungus right? It also appears to have delaminated or eaten away part of the coating on the rear element.

So I attempted to disassemble the lens, and after a couple of tries, I got the back element group off. The problem is, it's on the FRONT side of the back element, and there's another element attached in that group. Try as I might I couldn't get the two apart, and I was sure I'd break them if I tried any harder. Is it possible that they're glued together?

So I put it back together and stuck it on my K-x and it seems to take nice shots, at least on the crop sensor. I couldn't see any evidence of the fungus blurring the photos or being visible.

The question is, will I see it on full frame? I don't want to waste any film finding out.

Also BTW, I also found a Super Takumar 200/4 but the aperture ring doesn't work Too bad, because it's in GREAT shape cosmetically and optically. If anyone has any suggestions on how to fix that I'd appreciate it.

05-18-2011, 08:30 PM   #2
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Did you slide the Manual/Automatic switch to manual on the super Tak 200? If it is more complicated than that I can't help you, but you could try Eric Hendrickson at Home. Good luck!
05-18-2011, 08:52 PM   #3
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Oh yes, I slid the switch. In Auto, the pin doesn't work the aperture, and in either mode, the ring doesn't do anything.
05-18-2011, 09:56 PM   #4
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That's probably fungus, but its not severe so nothing to worry about, might wanna kill it with some UV.

As for the Takumar its hard to tell, I bet some part of the mechanism just snapped out of place. Disassembling Takumars is quite easy if you do don't mess with the focus coil and the optics, unfortunately you have to disassemble them starting from the front, so in this case it might be a little time consuming, but its a lot of fun, I guarantee you that

05-18-2011, 10:04 PM   #5
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It might be element separation which means two elements have been cemented together and the glue used has started deteriorating. In older lenses the elements were glued using canada balsam and you can break the bond by submerging the cemented group to boiling water for a few minutes. Then you can separate the elements by twisting a sharp blade in the seam (be careful not to scratch the glass).
The rest of the canada balsam can be cleaned with acetone once the elements are apart.

I've recently tried this with one lens and I just assembled the elements back in without any kind of glue and the lens seems to work just great. If you can get your hands on glue meant for optical equipment (hardens in UV-light) you can re-cement them but you have to be very careful to get them lined up perfectly.

Don't use the UV-curing glass glue available in hardware stores. Don't ask me how I know
05-19-2011, 04:16 AM   #6
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Interesting. I'll put it on the windowsill for a couple of days to kill the UV if it's there, but as you said ovim, it doesn't look like your typical fungus.

And if the elements are glued together, I can tell you they would need to be re-glued (otherwise focusing wouldln't work. I'm not about to do that.

So because this is in the back element it wouldn't be too visible? Should I go ahead and shoot with this lens on my vacation?
05-19-2011, 04:18 AM   #7
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QuoteOriginally posted by VaSA Quote
you have to disassemble them starting from the front, so in this case it might be a little time consuming, but its a lot of fun, I guarantee you that
*shudder* I'm going to have to disagree with you on that one. Taking apart this little 55/1.8 was no treat. tiny ball bearings that fall out and have to be reseated against springs and held in just the right spot . . . . I have recurring stress dreams about that.
05-19-2011, 05:26 AM   #8
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QuoteOriginally posted by Ryan Trevisol Quote
*shudder* I'm going to have to disagree with you on that one. Taking apart this little 55/1.8 was no treat. tiny ball bearings that fall out and have to be reseated against springs and held in just the right spot . . . . I have recurring stress dreams about that.
The Takumars have only one ball bearing, so when you're taking off the aperture ring, you gotta put the lens in a plastic bag and take it off inside the bag so the ball doesn't fly across the room (happened to me once).

05-19-2011, 06:25 AM   #9
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Uh huh. Then you get to get on all fours and fell around for it amongst the crumbs and cat hair you thought you vaccuumed up.
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