Exterior mystery crust
The Leica lens, E. Leitz Wetzlar “Summar” 50mm (5cm) f/2 is notorious for having internal haze, clouding images sometimes giving a desired warmth called “Leica Glow”. Some desire it for using as a portrait lens or other such use as the effect is warranted.
Before I show you how I got my 1939 Leica Summar lens apart to clean the haze, I first cleaned some kind of dried gunk on the front element that resembled very bad cleaning marks.
I had seen it before on my former 1936 Summar and other people complaining about their’s calling it cleaning marks, so it must be a somewhat common thing. This time it was more crusty, uneven looking that led me to believe it wasn’t just the glass itself.
I looked at it with a loupe and could see it was raised, some kind of crust or crystallization. I scratched at it with my fingernail and sure enough it flaked slightly. Perhaps a buildup of years of cleaning fluid?
I knew conventional cleaning wouldn’t work so I tried the method for removing Fungus on a lens. A 50/50 mix of household Ammonia and Hydrogen Peroxide then rinse with tap water. It immediately started working, almost foaming around the edge where it was thickest.
I had to repeat twice, as is usual, but a nice clean outer lens now with just a few true cleaning marks.
Clean the interior haze
Now I must say, while searching for tutorials and methods of cleaning the haze, it was kind of confusing because it was rarely stated that, in fact, the front name plate is attached to the front ring and the element itself.
It was also stated several times to unscrew the front element right from the lens base and people were having trouble because it would just unscrew the front group. I came up with a way to easily remove the front element.
First unscrew the front lens group from the base, just above the aperture ring. Extent the lens tube fully so it won’t spin in the base and grasp the outer knurled ring and turn it counter-clockwise ‘ccw’ it should unscrew fairly easy.
Unscrew fully and remove from lens base.
NOW is the time to unscrew the set screw ‘ccw’ in the nameplate (red arrow) so it will separate from the front lens group. It’s tiny don’t loose it.
Now you need some kind of grip tool to aid in holding the front group housing while removing the front element. I used an electrical cable, about the same diameter as a pencil or slightly smaller but not too small.
not clear here but, the front lens group housing extends backwards with a nice metal tube to grab onto with your tool just behind the front element ring. Firmly grip your tool around the group housing and firmly grip the front ring and unscrew ‘ccw’.
The entire front knurled ring, nameplate and front element are attached together. Mine came right off, I’ve read it could be difficult and a good soaking of the front element in isopropyl alcohol might help.
Again, I used the 50/50 mix ammonia / hydrogen peroxide to clean the haze from all inner elements except the lens behind the aperture blades as I didn’t want to risk damaging the aperture unit/blades.
Blow out any dust and fuzzies from cleaning before reassembly. I found what looked like dust in mine that turned out to be bubbles in the lens glass. I’ve read this is normal. Here’s a before and after the cleaning shot.
It looks great mounted on my 1953 Leica IIIf. It does have a few cleaning marks and some mishandled scratches in the middle but it was cheap and it’s mine.