Zuiko diaphragm slowness

[Nesster]

I have a couple of Zuikos - coincidentally both via Keh - that over the years have developed a slow diaphragm.

I've had the impression this is due to fatigue in a spring... but could be sticky blades.

One's a 50/1.4 and the other an 85/2.

Any tips? Or should I bring them to a proper repair place?

[Attila]

I think grease from focusing helicon went onto blades. Use it more and look when they are stop working time to clean them.

[dnas]

Yes, it's oil on the blades. I've cleaned a few OM lenses because of this.