Barrel stiffness in Leitz 90mm f/4 Elmar-C

[Ulophot]

When not regularly used, I take my lenses out to exercise them a bit every month or so. Today, my 90 Elmar exhibited some unexpected stiffness, or I should say, resistance, in the focusing ring. First, it was at both ends of the turn. This subsided after some exercise to just the near end of the distance range and disappeared as I held the lens horizontal but turned approximately upside-down (180 degrees) from its normal mounted position. As I say, it doesn't feel like lubricant stiffness but resistance as I reach the closest focusing distance.

What could be causing this?
Thanks.

 

[santino]

Probably dirt. I think the helicoid is brass so it shouldn’t wear to that degree.
Btw great lens.

 

[Ulophot]

I'd be a little surprised by that. While I did purchase the lens used (in beautiful condition) a couple of years ago, it has been completely smooth till now, and used very little, certainly not in any situation of dirty or sandy breeze or wind, rain, or other such.

 

[raydm6]

I have a lens (forget which camera) which - when tilted certain directions - will feel stiff while focusing; almost similar to yours.

I wonder if too much lubricant was used or wrong viscosity? Then again, the lubricant may have dried up and is binding on the helicoid. Just a hunch.

 

[Godfrey]

Regardless, it's time to send it off for a CLA and replace that old lubricant with new, modern, synthetic focusing mount lube.

I have the early M-Rokkor version of this lens. It's a really nice lens.. 🙂

G

 

[Ulophot]

OK. I'll send it off. Thanks.