What about the black Nickel Sonnar 5cm f/1,5 - f/9,5?

Räuber

Räuber

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I have created this overview of Sonnar 5cm f/1,5 lenses and at first glance everything might look nice and tidy. But it is not! I don't want to talk about the mess caused by Zeiss. I want to talk about one giant elephant in the room the Sonnar f8+ or f/9,5.

I did not know about this Sonnar for a long time. I could not find it mentioned anywhere in literature. Only one Japanese site mentions it: oldlens.com. And yes it exists. In short the very first version of the Sonnar 5cm f/1,5 that went into production was the black and Nickel f8 version. Bertele was not happy with the IQ of the first productive optical design so he calculated a second one that went into production. Most of the people will have seen the black and Nickel f11 Sonnar. This uses the second optical design. But in between there was a batch of 300 f8 lenses where Zeiss changed the aperture scale over the course of production from f8 to an unlabeled short f9,5 mark. The question I try to answer for some years now is what is with this batch of lenses? Or what optical design is used by this batch? Does the first lenses of this block still use the v1 optical design or do all of those lenses use the new v2 optical calculation? It might be important to answer the question how many v1 lenses where produced?

If you look into the Zeiss Fabrikationsbuch II the answer to this question is easy. This batch ( 1415701 - 1416000 ) uses the SECOND ( v2 = 08.12.1932) optical calculation. If you look from the outside on the body you are tempted to think that if the scale say its an f8 lens it has to use the first (v1 = 10.10.1932) optical calculation. What do you think? If you were offered an black Nickel Sonnar 5cm f/1,5 with an f8 aperture scale from this batch, what would you think?
 
I would grab it immediately if the price was reasonable. Then compare the optics.

My First Batch lens stops at F8, as expected.
Looking at the picture of the mystery lens- the body looks like the original design, with the Aperture extended to F9.5. This could have been done by extending the travel of the aperture mechanism, the difference is small. The body of the lens going to F11 looks slightly larger diameter.

There are other 5cm F1.5 Sonnars with unmarked F-Stops. The 255xxxx are marked "F11" but stop down to F16. I have two in that batch, a "T" coated and an uncoated lens. Both stop down past the marked F11. My two 190xxxx lenses stop at F11.
 
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They might look the same at the first sight but there are small differences between both Sonnar 5cm F/1,5. Left the F11 variation, rigth the F8+ variation. There are differences in the 1/10 mm area betweem both adding up in a way that the F11 is 0.7mm smaller than the F8+. Same is true for the infinity distance of both lenses. I'm not sure if those differences are low latencies of the 1932 - 33 production or if this is from shimming the lenses to fit the Contax camera body.

The biggest surprice was the rear end of both black and Nickel lenses.
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The F11 has an unusual black ring that the F8+ is missing. You can read the stamped serial at the rear end of the F8+ lens but not at the F11 lens. I checked stored images of other F11 Sonnars and they are missing this ring. Have you seen such kind of ring before? What is the purpose?

That might make this Sonnar another rare variation. But for me this is quite annoying. For my documentation I try to find sample lenses that match the base variation I want to show as best as possible. Time and again I buy a lens and then find some unusual modifications...

It looks like the ring is screwed into the rear tube. So it might be removable. I noticed that this ring allowes me to unscrew the rear glass element though. Is this supposed to happen? I can unscrew the rear element from my F11 lens. It kinda scares the hell out of me when I can unscrew my lenses. 😱

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Räuber said:
Can I unscrew the rear element the same way with the Sonnar f8+?
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You should be able to unscrew the lens like any other Contax mount Sonnar, there should be a tiny screw near the rear of the lens. This one is from a 139 series f2 Sonnar in Contax mount.

This one is from a 165 series f2 Sonnar in Contax mount

Of course, you could always wait for Sonnar B to check into this thread 🙂
 
On my 5cm F1.5 first batch: the rear retaining screw holds the rear fixture in place. It "just edges it", seems to be intentional. Mine was repaired- the original set screw was placed improperly at some point, and was destroyed. Someone changed the calibration at some point, and Henry restored it to the original position.
 
On my f/11 there is no black rear ring and both the front and rear groups can be unscrewed with your fingers. Since there is no filter thread on the front I guess this was deemed an acceptable design. There are no set screws holding the two groups in place. Nor are there any empty holes or cutouts indicating that such a set-screw ever existed. The surface is smooth and unscratched.

There is one set screw which holds the mount part to the actual lens body. It's done in a similar way to dexdogs first example.
The amount the lens body is screwed into the mount ring also determines the register/back focus distance. It's a bit of a stupid design for a number of reasons I don't wanna derail this thread with. Anyway, I guess that's why the design was changed pretty quickly, even if it meant the lenses had to increase in size and weight.
 
I guess one thing I can add is that I have not held that many examples of 5cm black and nickel lenses - but I have had a bunch of the black and nickel Contaxes they belonged to. One reason these cameras are difficult to keep working is that there are differences in how each part is made even for a Contax I of the same generation. This makes taking parts from a junker to fix another camera impossible at times.

With that in mind, I assume the same is true for the early black and nickel era lenses - it feels like each and every one of these was made in a bespoke fashion. They may look similar in appearance, but when one looks closer you end up finding various differences in part shapes and how elements mate together.

This is not something I have encountered with the later chrome Contax II models where if you use a Contax II of a similar period the internal construction and shape of the parts is identical, or at least close enough that substitutions are possible. The lenses mirror this and while there are still variations it seems that the breadth of variations has narrowed down a lot.
 
If you look closely you can see that this lens has been recalibrated twice. I took out the little locking screw and tried to turn the dark ring inside the mount, but it wouldn't budge, but moving this ring was obviously the way to calibrate the lens, as there is no Series 1374.jpgplace for shims in this type of mount. My series 1407 copy looks exactly the same.
 
Sorry, it's nonsense what I wrote. What I called a "black ring" is just the rear end of the main body of the lens, what you turn to calibrate the lens is of course the bayonet part. I just tried but it is stuck.
 
I tried to unscrew my f8+ lens but it does not move a mm. My luck again. It is stuck and I gave up after some serious tries. I could use a pliers but I'm afraid I will ruin the lens. Some of the black paint got off already when trying to turn the rear end. I guess my only hope would be to get a spanner tool and unscrew the rear element the "official" way.

I feel what is missing are the details of Berteles calculations. We know how many and when he did his calculations but the diameters and size of the glass elements is unknown to me. I made a desperate attempt to find some glues about it by measuring the front and rear glass pupil of every Sonnar and Jupiter I own. The result can be found as the columns "Dia Front" and "Dia Rear" in the spreadsheet of collected variations of Sonnar 5cm f/1,5 lenses. This works pretty well to identify different optical designs. But even then I can not say for sure if my f8+ is different from a f11. The difference is to small between both and might be in a range of production and measuring error margin.

So is there someone crazy and stupid enough to measure the front and back glass pupil of his v1 Sonnar (1374k, 1407k) and tell me the results? I used the inside jaws of my digital calipher to measure the diameter of the front glass and rear glass from outside (since I cannot open the lens). Carefully done chances are low to scratch the glass or lens. 🙈

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I'm not sure if the diameters of a v1 Sonnar 5cm f/1.5 differ from a v2. But that is my hope.

You can lookup my measurements in the spreadsheet.

 
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