CZJ MC Biometar f2,8 120mm: Cleaning stuck aperture guide

[Gonzoo]

1. Unscrew 4 screws near the mount and lift off the mount.
2. Remove spacer ring (black side pointing up).
3. Unscrew rear lens block by hand (or spanner).
4. Remove 3 screws located on the inside.
5. Lift off the rear lens barrel.
6. Use Isopropanol or the like to dilute dryed lubricant on the iris blades.
7. Actuate the aperture lever to open/close the iris for cleaning until aperture ring works again.
8. Reassemble in reverse order.

Take extra care with the little springs in the aperture coupling mechanism.

[Attila]

Many thanks!!!

[Srdjan]

Do you have any problem with reaching infinity? Can you take a picture of rear glass in infinity position. I have problem I dissemble the lens and assemble it again and cant reach infinity.

[Gonzoo]

Most likely you did not hit the right thread when screwing the helicoid back together.

I can take some pictures of the real element later.

[Srdjan]

Thank you very much. I m interested in a distance between edge of beck part that goes in and out and edge of lens in infinity position.

[Gonzoo]

First one is at minimum focus distance, second one at infinity.