Summilux 35mm asph - Problem

[techpan]

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I recently noticed small marks on the aperature blades that look like oil residue. The marks are geometric, appearing in the same spot on each aperature blade. Are these marks actually oil marks and should this be a concern. The lens works correctly but I don't want this issue to lead to something bigger.

[Shootist]

Supposedly oil on the aperture blades can lead to reflections inside the lens and make the blades sticky.

I have not had either problem even with one lens that has some oil marks on the blades.

I wouldn't worry about it right now. If in the future you see or feel a problem then send it in. If this is a fairly new lens and is still covered by the Passport warranty then make sure you send it in before that expires.

[gwelland]

I would watch out for the sticky aperture blade phenomenon at some point - this used to be a common problem with the Nikon 35/2 AF lens that was caused by a similar lubrication problem. It tends to look like a tear drop on each blade. Possibly more significant with an SLR lens as the blades have to move more often and quickly too.

 

As mentioned, probably worth getting it addressed before the passport warranty expires although the reality is that the lens will perform fine even with the marks.