Industar-50 aperture ring

[tho60]

Hello!

Some buddies made complaints of wiggly (easily rotating) aperture ring of rigid barrel Industar-50 LTM lenses. In my case the situation is the reverse: the ring is very stiff, hardly can I rotate it. I tried to inject some petrol under the ring, but after some temporary improvement I could not affect the situation; having evaporated the petrol changed nothing.

Could you suggest anything? How could I reach the ring (I have already read Maizenberg and Tomtiger)?
Thanks a lot!

 

[batterytypehah!]

Could be rusty aperture blades. It's been a while since I had mine apart, and I didn't need to work on the aperture (too loose on mine), but I think once you take the lens apart, it's a lot like the older I-22/I-50 collapsible. There's a very good site for servicing the I-22 but unfortunately it's in German:

http://www.bleckedermoor.de/fotomuseum/industar-22.htm

Use Google Translate and take lots of digicam photos as you go.

I would add that unless your lens has very nice glass and/or you just enjoy tinkering, you may just want to look for another; they're cheap. Or make one good lens from two damaged ones. I think the optical module is the same in all versions (RF and SLR), too.

 

[wolves3012]

If you remove the front optics you'll probably be able to get at the part that needs lubing. Undo the outer of the two rings immediately surrounding the glass to get the pair of optics out together. They're a pretty easy lens to dismantle, no special tricks or hidden fasteners.