Industar 26M : Bit-of-a-bind

[reagan]

An I26M I recently purchased seems to drag a bit when being screwed on. It turns freely til about half-way on then gets in just a bit of a bind - then frees up, a little more drag, then frees up and goes on.

This is constant on two different cameras, both of which take other lenses freely.

I don't force anything - okay lawn mowers, yes, but cameras? Never. Meaning, I feel lenses should go on using the tips of three fingers - if they won't something's wrong. .Anyway, even looking at the threads of the lens through a magnifying glass, I don't see any blemishes. So I'm planning on going over the threads with a very fine polishing of some type.

Question is: Any suggestions? 😕

Thanks

 

[reagan]

Good idea greyhoundman... thanks. I'm off to go do that. See? That's the very reasons we pay you the big bucks!

 

[DaveP]

Loosen all the screws on the lens mount then tighten them evenly , usually the mount is not tightened evenly and causes this...............

 

[reagan]

Threads cleaned, measured and screws re-torqued. Noticeable difference going on the Z4, but still not good on the Z3M. (The lens was bought for the Z4 anyway... ) However, after processing the first roll taken with the lens, it seems to have other imperfections, i.e. not focusing correctly. I noticed the focus somewhat stiff right off when I got it, so I believe I'll give it a good clean and lube and really examine it closely in the process.

I have very little investment in it, but it is sure nice cosmetically so I'm really hoping it will turn out to be at least a fair performer.

GreyHM & DaveP - Thanks so much for your input. Maybe I'll post back later after some tinkering.... that is if it improves! If not, I'll just add it to the other "paper weights" on my desk. 😉