look at all of that (shiny) oil on the blades!
Having successfully disassembled, cleaned, and reassembled the lens, I thought I'd create a little how-to. In my search for information on this problem, I found many (albeit pretty vague) lens disassembly guides, but was unable to find any Konica-specific information.
Tools:
- Lens spanner wrenches - these are a camera-specific tool, but in a pinch, a lens cap with rubber/tape under it, or a screwdriver/punch will work. I've even heard of using plastic pill bottles or cups.
- Jewler's screwdrivers - a small set of slotted and phillips screwdrivers to work with the several small screws involved here
- lighter fluid & q-tips - this will be used for cleaning the aperture blades once we have the lens open
- lens cleaning fluid/lens pen - for cleaning lens elements
- rocket blower
- soft cloth/shirt - I used this to handle the individual lens elements
Instructions:
Start by un-mounting the lens, removing the front and rear caps, and any filters on the front of the lens. Prepare your work surface - making sure your tools are nearby and there's plenty of light and space to work.
With that out of the way, begin the disassembly by removing the 4 screws that attach the lens mount to the back of the lens. Be careful when removing the mount as the aperture ring will come with it and there's a small ball under the aperture ring may fall out. If you lose this ball, you'll lose the nice detents at each aperture setting on the aperture ring.
The 2 set screws in the image above are from the removal of the fixed ring between the distance scale and aperture ring. It is not necessary to remove this piece for this operation. Here is what the lens should now look like:
See those 2 notches in the stepped-ring around the rear lens element? Those are where you need to insert your spanner wrench and unscrew the ring. I was able to apply gentle pressure with a small screwdriver tip to loosen the ring, finishing it by hand. BE CAREFUL NOT TO SCRATCH THE GLASS WITH YOUR TOOLS!!!
With the retaining ring now off, carefully use the shirt/soft cloth and flip the lens over onto it. The rear element, a spacer ring, and the next-rearmost element should fall out onto the cloth. You now have direct access to the back side of the aperture blades!
Now it's time to tackle the 5th and final lens element, which is bonded to the silver ring shown in the above image. This ring was on particularly tight in my lens, so the screwdriver/punch method didn't work. For this, I resorted to cutting out 3/4" strips of rubber band and placing them on the rim of the silver ring. I then used the lens' rear cap to apply downward pressure onto the rubber and twist the ring off. Here's a shot of that procedure:
The 2 set screws in the image above are from the removal of the fixed ring between the distance scale and aperture ring. It is not necessary to remove this piece for this operation. Here is what the lens should now look like:
See those 2 notches in the stepped-ring around the rear lens element? Those are where you need to insert your spanner wrench and unscrew the ring. I was able to apply gentle pressure with a small screwdriver tip to loosen the ring, finishing it by hand. BE CAREFUL NOT TO SCRATCH THE GLASS WITH YOUR TOOLS!!!With the retaining ring now off, carefully use the shirt/soft cloth and flip the lens over onto it. The rear element, a spacer ring, and the next-rearmost element should fall out onto the cloth. You now have direct access to the back side of the aperture blades!
Now that the rear of the lens is all set, it's time to tackle the front. Begin by using the spanner wrench or punch/screwdriver method again to loosen the nameplate ring (see those 2 little notches again?) on the front. Be extra careful with this piece as it's only plastic and likely breaks easily!
With the nameplate ring removed, you should see 3 set screws that it covered up. Remove these with a small screwdriver. Grasping the front lens ring in 1 hand and the rest of the lens in the other, unscrew the front ring from the rest of the lens body.
This now gives you access to a third ring which holds the front lens element in (finally!). Use the spanner wrenches/screwdriver/punch to spin this ring off as well (mine was loose enough where I could take it off entirely by hand). Be careful removing this ring as it holds 2 lens elements and a spacer below it! Using your soft cloth again, flip the lens upside down onto the cloth, releasing the spacer and the 2 frontmost lens elements.
Now it's time to tackle the 5th and final lens element, which is bonded to the silver ring shown in the above image. This ring was on particularly tight in my lens, so the screwdriver/punch method didn't work. For this, I resorted to cutting out 3/4" strips of rubber band and placing them on the rim of the silver ring. I then used the lens' rear cap to apply downward pressure onto the rubber and twist the ring off. Here's a shot of that procedure:
With this last remaining lens element removed, you now have total access to both the front and back surfaces of the aperture blades.
To remove any grease or oil on the blades, use q-tips lightly wetted with lighter fluid (or so I've heard...more on this in a minute) and swab and dry the blades thoroughly, cycling through the range of available apertures with the aperture lever. I used acetone to clean mine and it worked, but tarnished/ate some of the surrounding paint in the process. I've read mixed opinions on whether the aperture blades should be lubricated with graphite after cleaning. I left mine bare and the lens functions fine, so I don't feel it's necessary, but feel free to do so if you wish!
And as they say, installation is the reverse order of removal! Good luck!
