Cleaning a pentax smc 200mm f4

marcusBMG · Joined: 07 Dec 2012 Posts: 1304 Location: Conwy N Wales

This is a relatively simple lens to clean.

1. 3 screws revealed at minimum focus....
2. ..release the front barrel.
3. The whole front optical block can now be unscrewed from the helicoid assembly
4. I put acetone around the lip of the front element to soften thread locker, but when I tried to uncrew it the block separated in the middle. 2 elements in each side. It was the second element I needed to remove to get at the rear side of the front element, readily accomplished with a lens spanner.
Further disassembly of the block is likely to require perseverence with thread locker solvent like acetone and elbow grease.
5. 3 small screws to remove the rear light baffle. Note that the plate with a rectangular hole in is just glued in place - likely to come loose.
6. There is another baffle connecting to the rear element. When I applied a lens spanner to this it came out with the rear element...
7. ... so simple to clean. Note I didn't need to remove the mount.
8. A view of the iris.

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