Accessing the iris in a CZJ 180 Sonnar

[japomono]

Hi,

I have another question, this time for a 180/2.8 Pentacon 6 Sonnar. The aperture is regularly jamming. There is no oil on the blades, it seems, on the opposite, to feel too dry and too rough. I guess the inner parts need some cleaning and adjustment.

I have opened the lens up to the focus helicoil, but it is not clear how to go further from there. Does anybody know ? Does one need a special tool ?

It is an early, pre-Zebra model.

Thanks !

Benjamin

[Brian]

Can you post some pictures of it? I've never taken one of these apart. Sometimes there are hidden set screws under aperture rings and other places that keep things in place.

[japomono]

I forgot the thread, but I finally found the solution.

This model's build is indeed different from the later zebra version, although the optical elements seem interchangeable.

For the old version (sometimes called "star wars" version) you have to unscrew the nameplate ring in front (use some latex gloves for instance). You can then unscrew the front optical element and proceed further. It is somewhat similar to the Takumar 50/1.4 for instance.