Leica Summicron 90mm f2 Canada Midland

Leica Summicron 90mm f2 Canada Midland

Problem: Rangefinder lever stuck

This is a very rare lens, although the "normal" 90mm Summicron is quite popular and pretty cheep (retaliative to a Leica glass), the Canada Midland is a rare piece. It's quite hard to find any good info on it online. On one site I found that a total of 490 lenses where produced between 1957 and 1962. Based on the serial number it was made at 1958, but I'm not 100% sure about it.

It's a M39 - a screw mount, so I can use it on my Sony NEX camera, it's a crop sensor so I will get something 135mm equivalent of focal length, its quite long for my taste, but can do for half body or head shoots.  



Anyway,

The lens I've got was in quite good condition, you can see it was dropped and the mount if bent a bit inside, but it still can be screwed in fairly easy. The glass is in good shape, as well as the aperture. The problem is that if one really wan't to use it on a Leica camera, he needs to couple the lens to the range finder, this is done via this "prong" at the back of the lens. It's simply moves with the focusing ring, pushing on the range finder lever inside the camera. So this part was stuck, probably due to the hit the lens took.



Basically the disassemble part is easy and minimal, you just need to get the "prong" out. By removing the two side screws.



Next I took the think apart to clean it. Pushing it all the way in, you'll see the end of the spring visible at the bottom. You just need to lift it out of the hole (I used a knife's edge)

And these are the three part, the spring, the moving and static parts.

After cleaning the whole think (I also used some very fine sending paper to really make it smooth) the whole think goes back together, insert on part into the other and then lock everything with the spring.

Next I've tried to unbend a bit the mount as it to close to the "prong". For this I've made a tool which can be useful also for bend filter rings, so its a good think you remember this.

All you need is a piece of wood, I've used a round saw to drill a 40 mm (the mount is M39 - 39 mm) hole in the middle of the block and then cut it in half. Make sure you save the inside piece that you've sawed off.

Next I've placed the lens into the block, and the inner piece inside the lens, and gave it a few taps.

And that's about it. Its not perfect, but it will do.

So I did shoot few test shoots with this lens, and I really enjoyed it, It's a bit on the long side as I said, but it was quite easy to get sharp images even at F2 and the colors and total feel from the lens came out very nice.

(Sony NEX3 - Leica Summicron 9cm f2 @ f2)

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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).

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