Today, I have a quick tutorial on how to relube the older Pentacon 29mm f/2.8 lenses. The focus on these is usually either really stiff or bone-dry.
Remove the three screws on the back. Be careful with this plastic tab, especially when reassembling the lens, as they break easily.
With the back removed, you can lift off the aperture ring. But be careful.
Do not lose the tiny ball for the aperture click. Slowly lift the aperture ring. While you’re at it, remove the spring as well. Otherwise, you will most likely lose it while cleaning the helicoid.
With the aperture ring out of the way, remove this metal piece which fixes the inner helicoid in position.
Make sure to set the focusing ring to infinity before removing the inner helicoid. Slowly turn and remove the inner helicoid, and make a mark where they separate.
Remove the two screws responsible for the infinity and minimum focus stops. Unscrew the focusing ring, and count how many times you pass ‚infinity‘.
To remove the optical block, you will need to unscrew the front section. Usually, there is a screw underneath the name ring that needs to be removed first. Mine was already missing.
Remove the helicoid from the optical block to ensure no damage comes to the lenses during cleaning.
All separated. Clean them properly, then put them back together in reverse order. I used Polar Bear Camera’s medium lube for the inner helicoid and soft for the outer.
Hope that helps.
