Leica Summarit 50mm f1.5

Leica Summarit 50mm f1.5

Problem: Heavy haze on elements

A lot has been written about the Summarit lens. It was manufactured for 18 years (1939-1957 - Actually no lens were manufactured during WWII so its less than 18 years) with total of just under 75K copies made. A good place to read about the lens is here: slrlensreview.com.

The copy I've got dates back to 1954 and had a heavy haze on the elements around the aperture. This actually quite common in my experience with Leica lenses. The haze is an oily residue coming from the grease and lubricants evaporating and landing on the elements adjacent to the aperture. 8 out 10 times (not a real statistics) you can get it of with some alcohol.

Fig 1 - The Subject.

Fig 2 - Its kinda hard to see, but there is a lot of haze in there.

So now we know the problem, we need to get to the elements. The strategy, as in most cases will be to remove the back elements group. Most of Leica lenses I came across have to main assemblies, the focusing assembly and the optics+aperture assembly. As you can not remove the back elements without removing some parts of the focus assembly - the disassembly begins.

NOTE: I started with no references and just removed all the screws - This is not the right think to do. So ready the text because the photos can have some unnecessary stages.

(Don't do this step) - The first obvious screws are the three flat heads on the lens mount. I started by removing them and unscrewing the lens mount. With this done you actually removed a main part of the focusing mechanism, which means you'll have to assemble it just right later on.

Fig 3 - The three flat heads on the lens mount (don't remove)

Fig 4 - The lens mount removed, you still can't get to the retainer ring of the back element. So actually it got us nowhere.

The next screws in line are two screws on the focusing ring. You can remove only one of them.
Next are three set screws between the focusing and the aperture ring. You need to remove all three screws. Thats it. Don't touch the screws on the aperture ring.

Fig 5 - More screws. Note the mount ring should be on (didn't I say it already?!)

Now we get to the tricky part. At this point the optical assembly will turn freely, but that it, you can ture it for ever and nothing will happen.
What you need to do is to take a pin or fine screwdriver (it should be something sturdy, not a paper clip). You insert the pin into the one screw hole you opened on the focusing ring. The pin should enter into a hole in the inner ring that you can't see. But you can feel it, or if you look closely you can actually see it thru the hole.
Now the optical assembly can't turn and you can unscrew it. Yes, it is screwed hard(!). Try not to use the aperture ring for grip. There are actually tabs at the front of the lens, use them (with a spanner or something)

Fig 6 - The pin in the hole. You can see the tab on the front

Fig 7 - This is what we want to end up with

Fig 8 - The focusing assembly. The screwdriver I used as a pin is still in place.

From here on it's very straight. Unscrewing the outer retainer ring you need to remove 3 elements. Note that they are placed in a very tight fit (I'd like to see the tolerances on that machining drawing). So you need be patient removing the elements. 

Fig 9 - First element out

Fig 10 - All three out, the innermost element is on the left.

Thats it, now you have the aperture. Clean it. Open it and clean the element and the elements you removed and just assemble everything back.

Fig 11 - The aperture wide open (well closed, but you get the idea).