Leica Showcase Mystery J-3/ Sonnar- feeling better after 6hr Acetone bath.

BrianS

Legend
Jul 7, 2010
Picked this lens up on Ebay for ~$200 shipped from England. Sold as way out of calibration, for use on a mirrorless camera. I'm pretty good at calibrating J-3's, and the glass was perfect. Turns out I've seen it before. The optics module was glued into place, meaning you cannot get to the shim. Try to force the lens, you'll break the guide pins. Take the helical out of the mount, take out guide pins, get to the inner helical. You get more torque, would not budge. At this point- the only option is to take out the glass and drop into solvent. This one took 6hrs in Nail Polish Remover, I've had one require 4 days. I spent a lot of time getting loose paint and glue residue out, it gummed up the helical and threads on the aperture ring. Lighter fluid, q-tips, and paper towels.

So- once apart, found the Zeiss serial number of the rear fixture that shows it to be a Zeiss Sonnar 5cm F1.5 Sonnar "T" Contax mount, from a batch of lenses made in 1943. You can also see the tap in the rear of the fixture for the set screw that held it into the Contax mount.

J3Namering_SonnarSN

The optical fixture is the Alloy used in the Zeiss Sonnars during WW-II.

J3_Sonnar

J3_Sonnar_hybrid

There were 5 of taps for the guide-pins, a "no-Whoops" lens would have 2. Glad I marked the correct one before disassembling. I've seen another with two sets, 4 taps- but never this many.
 

BrianS

Legend
Jul 7, 2010
This lens was converted to Leica/Fed mount well after 1950, ZOMZ J-3 focus mounts use 3 screws to hold the helical into the Mount.

J3Mount_ZOMZ1

All_Clean by fiftyonepointsix, on Flickr[/IMG] J3Mount_ZOMZ2[/URL]

[url=https://flic.kr/p/qtu6Cx] All_Clean
by fiftyonepointsix, on Flickr

This type of mount did not appear until 1956. So someone took the 1943 Sonnar that had been finished as a 1950 Contax/Kiev mount J-3, and then SCREWED UP the conversion to Leica mount and glued everything in place. hard to figure out why, adding a 0.5mm shim would have made this one perfect. re-indexing the aperture ring was hard. To get the lens to fit into the J-3 mount, that someone filed down the set screws. Ouch. Drilled one out, hard time with the second, everything is back together now.

This one was hard, will get some pictures with it tomorrow.[/URL]
 
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BrianS

Legend
Jul 7, 2010
A quick test, nailed the focus with the M Monochrom. This was one of the most difficult "can of worms" that I've worked on. The signature is like my wartime Sonnar.

Wide-open, just a UV filter.

J-3/1943 Sonnar, At F1.5

At F4,

J-3/1943 Sonnar, At F4

Wide-open, all of the surfaces on this one are coated. The glass is near perfect. Considering the focus was off my 2m at 5m, maybe it did not get much use.

J-3/1943 Sonnar, At F1.5
 

ChrisBail

Regular
Dec 24, 2014
It looks like it has ended up as a lovely lens.

I'll be watching eagerly for another one of your J-3's or Sonnars to eventually end up here on the classifieds again.
 

BrianS

Legend
Jul 7, 2010
J-3/1943 Sonnar, At F1.5

At infinity, F1.5. I moved the rear fixture in a bit closer. Focal length is close to the Leica standard.

This lens seems to be sharper wide-open, with a very fast drop-off in focus with distance. I need to do some side -by-side comparisons with earlier lenses.
 

Mr_Flibble

Top Veteran
Aug 16, 2013
The Lowlands
Rick
Nice job on the 'rescue', Brian.

What would you recommend to dissolve balsamic cement between two lens elements?
I need to clean one of my Zeiss Albada finders.
 

BrianS

Legend
Jul 7, 2010
I've used Lab grade Isopropyl Alcohol to remove canadian balsam residue from the cemented group of a Canon 135/3.5, cleaned it up nicely. I'm not sure about just letting a group sit in it, most likely will take a while.
 

Corkey69

Rookie
Dec 11, 2014
NW England
John Neal
Rick,

Doesn't Balsam become liquid at about 150 - 180 degrees C? I have heard of people putting elements in the oven for a while to separate them. You could then use the isopropanol to clean up the residue.
 

Hap

Top Veteran
Jan 9, 2016
Picked this lens up on Ebay for ~$200 shipped from England. Sold as way out of calibration, for use on a mirrorless camera. I'm pretty good at calibrating J-3's, and the glass was perfect. Turns out I've seen it before. The optics module was glued into place, meaning you cannot get to the shim. Try to force the lens, you'll break the guide pins. Take the helical out of the mount, take out guide pins, get to the inner helical. You get more torque, would not budge. At this point- the only option is to take out the glass and drop into solvent. This one took 6hrs in Nail Polish Remover, I've had one require 4 days. I spent a lot of time getting loose paint and glue residue out, it gummed up the helical and threads on the aperture ring. Lighter fluid, q-tips, and paper towels.

So- once apart, found the Zeiss serial number of the rear fixture that shows it to be a Zeiss Sonnar 5cm F1.5 Sonnar "T" Contax mount, from a batch of lenses made in 1943. You can also see the tap in the rear of the fixture for the set screw that held it into the Contax mount.

J3Namering_SonnarSN

The optical fixture is the Alloy used in the Zeiss Sonnars during WW-II.

J3_Sonnar

J3_Sonnar_hybrid

There were 5 of taps for the guide-pins, a "no-Whoops" lens would have 2. Glad I marked the correct one before disassembling. I've seen another with two sets, 4 taps- but never this many.


Brian .....how do I find you to consider Jupiter cleaning and adjusting lenses?

Best hap
 

BrianS

Legend
Jul 7, 2010
I am a hobbyist, as such have limited spares- mostly collected from parts lenses. I take on work from forum members, get to it when my Daughter has a lot of homework to do.

These lenses can be cans-of-worms, but usually better than the one in this thread. The worst tends to be stuck set screws, the biggest PINTA is when the Helical cannot drive the RF to infinity. That means the focus mount has to be polished down, the helical screwed in more deeply, and then new taps made to re-index the focus ring. The last lens I worked on was full of metal filings and a strip of metal from a tap being drilled out.

When evaluating a lens- try to figure out how far the focus is off on your camera. The camera that the lens is to be used on makes a difference: I find the M Monochrom and M9 are slightly different, translates to almost 0.02mm on the shim.
 

BrianS

Legend
Jul 7, 2010
Yes, the original lens coatings on this lens is PUURRRFECT- to quote Cat Woman. My 1938 Coated Sonnar shows some spotting on the inner element behind the aperture, my 1936 Coated Sonnar is close to Purrfect!
 

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