Sonnars: Transition, Coburg, Irregular Production. Examples and Notes.

[Sonnar Brian]

I've seen some "not quite right" Carl Zeiss Jena lenses over the years. These are NOT counterfeit, but were assembled using Zeiss components and probably by Zeiss Employees after the war OR were assembled in the USSR as machinery was being setup after being taken from Germany and with unfinished components from Germany.

I invite anyone with one of these lenses to post in this thread, and anyone that has a question about a lens like this to post here.

How do I know both sides of the "OR" are true: I own two lenses from the same batch, one completed as a Carl Zeiss Jena 5cm F1.5 Sonnar "T" and the second completed as a 1950 KMZ Jupiter-3 in Contax mount. The latter- perfect glass because the distance between the lens groups was wrong, and sewing thread was used to hold it into the Contax mount. Could never have been used on a camera, was in perfect condition. I increased the spacing for the rear triplet, remounted in a J-3 LTM mount. One of my best Sonnars. The rear fixture is stamped with the Zeiss SN 286xxxx listed in Thiele as a 5cm F1.5 Sonnar. It is now.

My Transition Sonnar: sent to me some 15 years ago by an RFF member. The middle triplet was not finished- ie 1/3 of the surface was not polished. I replaced it with a triplet from a parts lens. The focus uneven, tried my best. Still uneven, due to poor machining. I ended up trading one of my uncoated Sonnar LTM remonts for it. Good choice, that lens got a lot of great use. This Sonnar: optically- good now, focus is uneven and I wanted it for "the collection" as part of the Sonnar evolution.

 

[Sonnar Brian]

SO: this lens is not a counterfeit. This lens is irregular production, a one-off quality about it.

The glass is in good shape, it could not have gotten a lot of use with the original middle triplet.

This lens is missing 1 aperture blade. I always thought a junior employee of Zeiss made it, and needed some quick cash. Did not know how to install apertures.

Look at all those extra set screws holding the focus mount in! Wahoo with the drill.

Stop screw through the focus ring.

The cam is left unpainted.

Lack of Spanner Slots for the rear fixture, retaining ring has spanner slots.

No internal set screws holding the namering and rear fixture in place.

The Aperture ring turns well past F1.5. F22 is properly indexed.

See why I had to have it!

 

[Sonnar Brian]

Another one sent to me to work on several years ago. Same batch as mine. This one does not have "ears", so places it as being assembled later.

The middle triplet was "Hot Mounted", meaning installed in the barrel while the Canada Balsam was still fluid. This aligns the triplet using the machining of the barrel. This would not be done for regular production- but is a quick and dirty way of aligning the elements of a group. "I know first-hand that it works"

The Barrel is Heavy and in the finish of the metal.



I really enjoyed working on this one, as it is part of the story of rebuilding after WW-II. The owner insisted on paying me. I enclosed a Jupiter-3 in Contax mount along with this lens as payment for working on it.

 

[Sonnar Brian]

The Barrel and Focus mount of the Above transition Sonnar.

 

[Sonnar Brian]

The thing about these Sonnars: It's very difficult to know their history over the last 80 years.

The main batches of 5cm F1.5 Sonnars during the war start with 270xxxx, 272xxxx, 284xxxx, and 285xxxx through 286xxxx being the largest batches with some other smaller order in between. This is a rule-of-thumb! Most were completed as Contax Mount. My two "Very High Confidence" wartime LTM lenses start with 272 and the other starts with 285.

BUT: 272 batch,
1) Wartime LTM lens
2) The "Basket Case" Contax mount Sonnar, just rebuilt.
3) ZK 5cm F1.5 Sonnar from 1949, Inner Helical has the unique serial numbers as do the wartime lenses
4) 1950 KMZ Jupiter-3 with the serial number stamped in the rear triplet showing it to be from this batch.

The 285/286 Batch
1) Wartime LTM lens, High Confidence
2) 1950 KMZ Jupiter-3 with SN stamped in the rear fixture placing it in this batch.

How many LTM lenses were completed as Regular Production, versus how many were finished after the war in Russia as CZJ Sonnars or ZK Sonnars using the Zeiss helicals with SN stamped internally? I do not know. I have seen many ZK and "transition lenses" that were irregular production with the internal numbers. The SN of my two "high Condidence" lenses, numbered below 300.

SO what makes a Sonnar "high confidence" to me? see the scribe in the rear triplet fixture- that is how I aligned the lens to put the rear Set Screw back in place. NEVER try disassembling a Wartime Lens without looking for these hidden set screws.

The ones I have handled that appear to be "regular production" have a Set Screw holding the rear fixture in place. They also have a set screw holding the front namering in place. I have KMZ jupiter lenses that have the Hole for the set screw to hold the rear triplet in place, have the SN stamped in the rear fixture- BUT no Tap and no Screw. I figured it was made from Zeiss parts and assembled after the war in Russia. Odd little things like that: regular Production would be very concise, follow every step. Steps left out: Either Post-War making the best out of ruins, or assembling lenses by a new crew that "like me"- I don't need a set screw to hold the namering on, that is "German Over-Engineering". So "Authentic Regular Production", i look for German Over-Engineering.

 

[dexdog]

Brian, I have a 285 series 5cm/1.5 that is part of the same batch as the lens shown in your first post. Looks very much like your lens, has "ears". This lens performs well.

 

[Sonnar Brian]

Brian, I have a 285 series 5cm/1.5 that is part of the same batch as the lens shown in your first post. Looks very much like your lens, has "ears". This lens performs well.

My 285 LTM 5cm F1.5 "T" is a fine performer- despite a well-worn coating on the front element. It has the hidden set screws, and was very well used.

I believe the 272 batch and 285 batch had lenses completed by Zeiss before the war ended, but the batches not completed. Many components left unfinished, and completed after the war.

This is the 1950 KMZ Jupiter-3 from the 285~286 batch. It was held in the mount using Sewing Thread to tighten up. The focal length was too short, and the lens could not be focused on a Contax, could not be moved in close enough to the image place. I moved it to an LTM mount. Perfect Glass. First lens I used on the M Monochrom.

 

[Sonnar Brian]

This is my "High Confidence" Sonnar 5cm F1.5 LTM from the 285 batch.
Hidden set screws were in place.