How I Freed the Stuck Blades of a Vintage Domiplan 2.8/50
During a recent flea market hunt, I came across a Praktica LB paired with a Domiplan 2.8/50 lens by Meyer-Optik Görlitz. It looked promising, so I grabbed it. However, once home, I discovered a problem: the shutter was stuck open. Don’t ask me why I did not notice this before I bought it … Even after removing the lens from the camera body and manually pressing the stop-down pin, the blades wouldn’t move at all.
Domiplan 2.8/50 with stuck aperture blades
A starting point
Not ready to give up, I googled and found that many of these lenses seems to have this problem. Also, the lens really was in pristine condition, so I decided to dive into a repair myself. I based my disassembly on this excellent video guide, which walks through the process step-by-step.
Setting free the aperture blades
It looks scary but reassembling it back just needs patience (a lot actually…)
What I Discovered During the Fix
A few key things I learned along the way:
The small steel ball inside the lens is crucial — it’s responsible for the aperture ring’s “click” stops. Be very careful not to lose it during disassembly (as mentioned in the video as well). On my lens it did not pop out though.
When re-assembling the lens, make sure to slightly actuate the aperture blades to go in the center of the lens before screwing the next ring on top of them. Otherwise you fixate them and I guess that was what ruined my lens. I definitively saw some marks of other people doing some “repair” on the lens
The stop-down pin needs to be slightly pressed during operation (check out on the different versions of M42 lenses). If it isn’t, the aperture mechanism won't engage, and rotating the aperture ring will have no visible effect. Always simulate a bit of pin pressure when testing the aperture outside the camera. Another way is to screw in the lens before testing if closing the aperture blades work now.
The repair took some patience and a steady hand - especially the reassembly of the aperture blades. But it was a fun project and a good reminder of how mechanical and tactile these vintage lenses are. There’s something really satisfying about breathing life back into a classic! It might not be the best 50mm/2.8 lens there is, but I repaired it :)
Working aperture - yay :)
More flea market finds (and fixes) to come!