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Helen Highwater
Feb 18, 2014

And furthermore

Grimey Drawer

Not sure this is a thread that needs to exist but none of the existing threads seem to cover it and, I guess if no-one cares then it will sink off the front page in a few days.

I have a Jupiter-11 lens for the Kiev 10/15 mount - not the rangefinder or the K mount version. It differs from those versions primarily by having an automatic aperture linkage inside the focus thread.
Mine had some fungus on the inside of the rear element and the aperture blades were sticky. I took the rear element off easily enough and cleaned up the fungus, then I went to work on the aperture blades. To my relief, I didn't need to disassemble the aperture assembly, I just needed to unscrew the outer barrel/focus ring from the main element group and loosen them a little. This is where it went south. Unscrewing the outer barrel was pretty easy and I removed the focus ring too to clear away some excess grease but now I can't figure out how to get it back together.

There are two slots in the element group thread that accept long tabs which are part of the barrel assembly. If I unscrew these far enough to let the elements thread start on the focus ring thread, then the lens mount is way too far back - there's a huge gap between the range indicator and the range scale. If I move them forwards then it's almost impossible to get the lens elements screwed into place and, if I do, then they fall out when I focus to infinity. Is there a trick that I'm missing (other than don't take poo poo apart when you're sick)? I made index marks and noted positions of stuff as I went but I cannot figure out how to get these two parts together again properly.

Photo below. The focus ring/lens barrel is on the left, the element group is on the right and the lens mount is at the back - it screws onto the part of the lens barrel assembly that adjusts the position of the long tabs.



I've found disassembly guides but only for the M39/M42 versions that don't have the automatic aperture control.

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The Claptain
May 11, 2014



Lipstick Apathy

I had similar problem when fixing my CZJ Sonnar 180/2.8 lens - front assembly would sit either too far back, or would fall out when focusing to infinity. I can't exactly remember what the problem was, I wasn't documenting the disassembly (smart thing to do), but I remember that, besides assembly with index marks I made, focus ring had to be in the right spot. Try fiddling around with that.

And count yourself lucky for not having to take apart the aperture assembly - I think I spent hours putting it back.

SMERSH Mouth
Jun 25, 2005



I have a Fujinon S 100mm lens for the GL690. It has some fungus spots as well as some really gnarly internal dust. I've thought about opening it up to clean. It doesn't seem like it would be all that bad; the entire lens assembly focuses by moving back and forth in the helical as a complete unit.

But every nice & clean (that is, taken apart and cleaned by someone) 690 Fujinon that I've tried has had some pretty bad optical de-centering. So even though they seem simple, actually getting them back into perfect alignment must be more difficult than it seems. Here's an example from another 'CLA'd' 100 that I recently tried out. (The notes are for the seller. I'm returning it.)

NB: Flickr sharpening makes it harder to discern the blur.




These are test shots of flat surfaces, but that blur on the left is painfully obvious even on shots with depth to infinity. I mean, I guess it's de-centering. Definitely not me or the camera. The dirty 100 shows nothing like this. I even tested it on two separate cameras.

So, even though the seller, who is also a tech, talked up how fool-proof and solid these lenses were to service, something evidently went wrong here.

Just a little bit of an object lesson about the possible consequence of disassembling lenses, even if they are old and simple.

--

As for ill-advised DIY rescues, I've got an Olympus XA that I foolishly took apart in order to clean the faint RF patch. It's much clearer now, but since I had to pry off and reassemble the shutter button to get to the RF, I've killed its sensitivity. It's very spotty now. It seems like adjusting pressure on the screw that holds down the little gold leaf contact switch can get me to either either dull and unresponsive shutter tripping that only works half the time, or ultra-sensitive response that often trips the shutter from just the vibration of the film advancing.

SMERSH Mouth fucked around with this message at Feb 15, 2017 around 03:22

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