Rust corrosion on aperture blades of a 50/2 type 2 rigid Summicron, worrisome?

R

rich815

Guest
Someone has lent me a very nice 50/2 Summicron (type 2 - rigid) on a "try-to-see-if-I-want-to-buy" basis. The glass is absolutely perfect having been re-coated recently. Images in my first roll or two with this lens shows how fantastic this lens can be. However, when inspecting the lens closer, when viewed through the rear, I can see a bit of rust corrosion on one of the aperture blades. It's about 3-4mm long but does not seem to affect the movement of the blades. When viewed from the front I can see two very small (less than 1mm) evididence of rust as well on two of the blades yet way smaller than the one seen from the rear. Is this something to be very concerned with?
 
The rust will continue to spread if you don't remove it. The process is fairly simple. Remove the diaphragm blades, polish them with a bit of jewelers rouge on a toothpick, clean them with lighter fluid and then reblue them with gun smith bluing agent. The bluing will make them more resistant to rust. Then reinstall the blades.

I have a 90 f/2.8 Elmarit that had lots of rust and rust particles on the lens surfaces. I washed the lens elements under running water so that I would not scratch the coatings and I polished the blades to remove the rust. The lens is now one of my favorite lenses, soft wide open and razor sharp when stopped down to f/4.

You don't want to let the rust get to the point of freezing up the diaphragm blades, because then you end up having to find replacement blades.
 
Stating the obvious (one of my few skills), it sounds like the lens may be well worth the repair effort. I have a user DR 50/2 that I bought recently and feel much the same way about its performance. One can enjoy Leica glass at commoner prices with a little work and patience, as I've learned to my delight.
 
I am sure the lens can be easily serviced. Send an email, or call DAG or Golden Touch, explain the problem to get a professional opinion, and basic estimate for a good CLA that will resolve this. Keep that cost in mind if you buy the lens.
 
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