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01-26-2010, 03:57 PM   #1
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K 45-125mm Issue

So I recently acquired a K 45-125, M 50 1.4, and ME. I got the K cheap with the others because of something inside the lens. When I got it I thought it had fungus but when I took it to a local shop they told me that it was two lens elements coming unglued. It looks like small specks inside the lens in a fairly regular pattern from the center to about 1/4" from the outside of the lens element furthest from the camera (end with the filter). Does the shop's diagnosis sound reasonable? If not, is there any way to disassemble the lens to clean it? If so, is there a way to fix it? With the right instructions and tools I am fairly mechanically inclined and could probably figure it out. I would like to disassemble it any way since the aperture is a little slow and with the spots it's probably not worth it to get the shop to do it.

I would really like to get this lens to work since from what I have read it seems like a nice lens. Also, other than the spots and the aperture ring the lens and the other three items that it came with are mint. The "QC passed" inspection sticker on the aperture ring shows no wear, as well as the rest of the lens.

It is difficult to get the spots to show up in pictures but I could try again if they are needed (ideas are welcome).

01-26-2010, 04:44 PM   #2
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I like to check out the optical diagram to see if there are indeed glued elements, or some other less serious issue.

Wow, look at all those elements. This might not be a great lens for a first disassembly. I can see some grub screws just above the aperture ring. There might be some screws hidden under the focus grip. I can't tell whether this lens has the ring around the front element that unscrews through the filter threads.

Element separation is theoretically fixable. Just use a solvent to dissolve the old glue, clean the elements and reglue. Without leaving any air bubbles or variations in thickness. And aligned perfectly. With a glue that has great optical properties, never discolors with aging or UV, and is reversable for future repairs. I haven't tried it.
01-26-2010, 06:32 PM   #3
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I checked out the site you linked the photo from, if it matters the lens would be the older of the two models.

Holy mother of elements that looks insane!

Re-glueing sounds pretty involved and requiring things I don't have to get the elements aligned properly. I found a recommendation for Focal Point to repair it, though I'm not sure if it would be worth the cost. The lens does have a retaining ring that unscrews through the filter thread. What would be a good way to get this out? Is there a special tool? Being so close to the front element, I would not want to screw up getting it out.

This is about what the spots look like.

Thanks for the help!
01-28-2010, 06:40 PM   #4
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The lens is officially dead. I got the front element off, but the spots were still further in. The front elements have some separation as well as another element set further in...poop


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