Dez
Bodger Extraordinaire
I do not know if the newer versions of the Summicron 50 lens are constructed in the same way as below, as I have only worked on the original rigid version, and the Dual-Range one which differs only in its focusing mount.
As most people know, the old Summicron lens comes apart by merely unscrewing the optical block from the mount- no setscrews or retaining rings involved. It is also well known to anyone who saw Brian Sweeney's excellent thread on the subject-
http://www.rangefinderforum.com/forums/showthread.php?t=95882
-that the Summi comes apart at the aperture position by unscrewing the two halves of the optical block.
I recently bought a cosmetically near-mint DR Summicron from a very well respected vendor on ebay, one who tends to have conservative ratings. This lens was a bargain, as the vendor indicated that it had internal patchy fog issues. As with most lenses, fog tends to occur on the surfaces adjacent to the aperture blades, and the Summi is rather notorious for this.
When I got the lens, I did see moderate fogging, probably not really enough to worry about, but enough that I wanted to clean it. Unscrewing the two halves of the optical block, however, is much more easily said than done. I tried the usual methods, gripping the surfaces with rubber sheets or a split rubber stopper, but had no luck at all.
So I invested in the proper tools, ring wrenches sourced from Micro-Tools, and which they call Flexi-Clamps. Their part number FLB-17B 1.62" wrench is perfect for the front of the lens. The FLB-13B 1.19" wrench fits the larger diameter of the rear part, just behind the aperture ring, and FLB-12B, 1.12", fits the smaller diameter farther back on the rear group. These wrenches are beryllium-copper, so will not mar the surfaces. Using the two larger wrenches, the lens came apart immediately with no fuss at all.
I am pleased to report that all the fog was on these glass surfaces, and it came off with no trouble with very gentle use of ordinary lens cleaning fluid, and canned air. The lens has a small amount of dust between other elements, but I suspect that taking the lens completely to bits would be far more trouble than it is worth.
So to anyone wanting to get the best they possibly can from their old Summi, I would heartily recommend getting the wrenches and digging in. It is a very easy job with the right tools, and really frustrating without.
Cheers,
Dez
As most people know, the old Summicron lens comes apart by merely unscrewing the optical block from the mount- no setscrews or retaining rings involved. It is also well known to anyone who saw Brian Sweeney's excellent thread on the subject-
http://www.rangefinderforum.com/forums/showthread.php?t=95882
-that the Summi comes apart at the aperture position by unscrewing the two halves of the optical block.
I recently bought a cosmetically near-mint DR Summicron from a very well respected vendor on ebay, one who tends to have conservative ratings. This lens was a bargain, as the vendor indicated that it had internal patchy fog issues. As with most lenses, fog tends to occur on the surfaces adjacent to the aperture blades, and the Summi is rather notorious for this.
When I got the lens, I did see moderate fogging, probably not really enough to worry about, but enough that I wanted to clean it. Unscrewing the two halves of the optical block, however, is much more easily said than done. I tried the usual methods, gripping the surfaces with rubber sheets or a split rubber stopper, but had no luck at all.
So I invested in the proper tools, ring wrenches sourced from Micro-Tools, and which they call Flexi-Clamps. Their part number FLB-17B 1.62" wrench is perfect for the front of the lens. The FLB-13B 1.19" wrench fits the larger diameter of the rear part, just behind the aperture ring, and FLB-12B, 1.12", fits the smaller diameter farther back on the rear group. These wrenches are beryllium-copper, so will not mar the surfaces. Using the two larger wrenches, the lens came apart immediately with no fuss at all.
I am pleased to report that all the fog was on these glass surfaces, and it came off with no trouble with very gentle use of ordinary lens cleaning fluid, and canned air. The lens has a small amount of dust between other elements, but I suspect that taking the lens completely to bits would be far more trouble than it is worth.
So to anyone wanting to get the best they possibly can from their old Summi, I would heartily recommend getting the wrenches and digging in. It is a very easy job with the right tools, and really frustrating without.
Cheers,
Dez
