Zeiss Jena 5cm Sonnars – The Magic of the Prewar Uncoated Sonnar – By Brian Sweeney

Interchangeable lens 35mm rangefinder cameras became popular almost 90 years ago when Leitz introduced the Leica II and Zeiss debuted the Contax I. Both companies brought out full lines of lenses, and dominated the market for 35mm format. The design philosophies of the two companies were very different.

Leitz designers believed that lenses should be highly corrected with small amounts of residual aberration. Their designs made use of double-Gauss optics, lenses with highly symmetric designs. Pairs of similar image-forming optics, placed back-to-back, will cancel out aberrations.

Think of two prisms placed back-to-back: the first splits white light into a rainbow, the second prism combines the rainbow back to white light. The optical pairs are “highly symmetric”, not “completely symmetric”. In the 1920s it was found that introducing a small amount of asymmetry into the symmetric Planar formula lens allowed for much wider apertures.

The Summar, Xenon, and Summitar of the 1930s were well-corrected for distortion, highly color-corrected, and had a reputation for fine resolution. I have near-perfect examples of each of these lenses, and can attest to their optical qualities. The modern APO-Summicron demonstrates the commitment to this original Leitz design philosophy.

Zeiss designers placed more importance on producing a bright image with high contrast. The first Zeiss “objectives of extreme rapidity” were 4cm F1.4 Biotars, brought to market in the late 1920s in various Cine camera mounts. These lenses were double-Gauss designs, 6 elements in 4 groups, much like the later Leica Summar. For the Contax mount, Zeiss moved to designs that minimized the number of air/glass interfaces using groups of cemented elements in asymmetric designs. Corrections for flatness of field and geometric distortion were secondary to transmission of light.

Ludwig Bertele worked for Ernemann (Krupp-Ernemann Kinoapparate AG) and developed the “Ernostar” F2. This lens had 5 elements in 4 groups, an asymmetric 1-1-1-2 configuration, eight air/glass interfaces. Ernemann merged with Zeiss, and Bertele created their most famous lens of the 1930s by filling in the space between the 2nd and 3rd element of the Ernostar with low index of refraction glass. This reduced the Sonnar to 6 air/glass interfaces, improving transmission by almost 10%.

1934 Carl Zeiss Jena 5cm F2, converted to Leica Mount
1934 Carl Zeiss Jena 5cm F2, converted to Leica Mount

The classic Sonnar was the super-speed lens of choice of the 30s and 40s. The 5cm F2 Sonnar, introduced in 1931, was 6 elements in 3 groups, 1-3-2 configuration. The rear doublet used in the 5cm F2 Sonnar was split into a triplet, and the 5cm F1.5 Sonnar was born. The 5cm F1.5 Sonnar of 1932 was 7 elements in 3 groups, 1-3-3 configuration. Add them up- 6 air/glass interfaces for more transmission of light compared to the 10 surfaces of the Leitz 5cm F1.5 Xenon. The Sonnar is an “Asymmetric” design: the front section is a telephoto design with a focal length about 2.5x the overall focal length of the lens; the rear section is about the same as the final focal length. The front and rear sections are brought together using the lens maker’s formula, the asymmetry means they are closely spaced compared to a double Gauss. This configuration gives the Sonnar its compact attribute and optical properties.

1934 Carl Zeiss Jena 5cm F1.5, converted to Leica Mount

Technically, the Sonnar formula “suffers” from spherical aberration, coma, and field curvature. In practice, these imperfections produce a pleasing signature, a unique blend of “perfect imperfections”. The mechanical construction of both lenses was greatly improved in 1934, added a 40.5mm filter ring and a much easier to work on mount. Serial number for the improved design starts at “about” 1.6million. If it has a filter ring, it’s the new mechanical design. Zeiss started coating optics in 1936 to further increase optical transmission. Coated and uncoated lenses were produced concurrently.

Sonnars render images differently due to their asymmetric design. When used wide-open, field-curvature and spherical aberration spreads the depth-of-field across the frame, giving a “3-D” or “Plastic look”. A nice way of saying “soft”, but the Sonnar makes it look good. By F4, the image is sharp across the field. Used wide-open, the uncoated Sonnars have less contrast and muted colors compared to modern designs. Forget “flatness of field”- the point of best focus runs through the image like a dampened Sine-Wave. This gives rise to a unique Bokeh, full of comets and spheres circling the subject. If you plan on shooting Brick Walls, don’t use a Sonnar. Use it to capture the 3-dimensional world.

1934 5cm F1.5 Sonnar, Wide-Open on the Leica M9
1934 5cm F1.5 Sonnar, Wide-Open on the Leica M9
1934 Carl Zeiss Jena 5cm F2, Orange Filter, Wide-Open on the M Monochrom Stopping the Sonnar down to F4 increases sharpness and contrast.
1934 Carl Zeiss Jena 5cm F2, Orange Filter, Wide-Open on the M Monochrom
Stopping the Sonnar down to F4 increases sharpness and contrast.
1934 Carl Zeiss Jena 5cm F2, at F4 on the Leica M9
1934 Carl Zeiss Jena 5cm F2, at F4 on the Leica M9

Most of the pre-war Zeiss Sonnars are uncoated. Glass oxidizes with time, called “Bloom” on a lens. Early photographers noticed that older lenses tended to perform better than new ones. The “Bloom” of a lens acts as a natural lens coating and produces some beautiful colors on a modern camera. Always clean an uncoated lens with great care to leave the Bloom intact.

1934 Carl Zeiss Jena 5cm F1.5, Wide-Open on the M9, “Bloom” on Optics.
1934 Carl Zeiss Jena 5cm F1.5, Wide-Open on the M9, “Bloom” on Optics.

The Asymmetric layout and compact design of the Sonnar gives rise to its most difficult to master design flaw: focus shift. The focal length of the center of the Sonnar is longer than the focal length of the edges. This means the best focus point of light entering the Sonnar from the center is behind that of light entering from the edge. Used wide-open, the image is dominated by light coming in at the shorter focal length of the edges. This is responsible for the lower-contrast/spread-out depth-of-field of the Sonnar used wide-open. Stopping down the aperture eliminates contributions from the edge; the image that remains is the product of the longer focal-length center of the lens. It “shifts” towards infinity.

Zeiss C-Sonnar at F1.5 on the M Monochrom
Zeiss C-Sonnar at F1.5 on the M Monochrom
Zeiss C-Sonnar at F4 on the M Monochrom
Zeiss C-Sonnar at F4 on the M Monochrom – note the focus shift away from the front of the post

Finding an original Carl Zeiss Jena Sonnar in Leica mount is difficult: at most a couple of thousand were made during World War II and in the years following World War II. These lenses are often found in “rough” condition, metal alloys were used rather than heavy brass and nickel. Many were put together after the War, as the factories were being rebuilt – or relocated. If you find a good one, be prepared to pay as much for it as you would a new Zeiss C-Sonnar.

These lenses are all “T” (for transparent) coated optics. The construction of the wartime Zeiss made Leica mount lenses can be described as “fragile” due to the material and design of the focus mount. I have two of these wartime lenses. One was filled with sand and grit when received, and the helical was worn to the point that it required a “sleeve” for the mount to keep the RF cam aligned as you focused the lens.

Pre-war Sonnars are found in Contax RF mount and must be adapted for use on a Leica. The 5cm Contax mount lenses are “internal mount,” they use the helical built into the camera body of the Contax. The F1.5 lens used a hard glass for the front element; the F2 lens used soft glass. The F1.5 lenses that I’ve bought generally clean to crystal clarity, the F2 lens is more like the Summar – typically seen with cleaning marks and scratches. I think it very wise that Skyllaney is coming out with a new 50mm F2 Sonnar formula lens, finding clean originals is difficult.

1936 Carl Zeiss Jena 5cm F1.5, uncoated optics, wide-open on the Leica M9
1936 Carl Zeiss Jena 5cm F1.5, uncoated optics, wide-open on the Leica M9
1936 Carl Zeiss Jena 5cm F1.5, Converted to Leica Mount
1936 Carl Zeiss Jena 5cm F1.5, Converted to Leica Mount
 1936 Carl Zeiss Jena 5cm F1.5, wide-open on the M9, coated optics.
1936 Carl Zeiss Jena 5cm F1.5, wide-open on the M9, coated optics.
1936 Carl Zeiss Jena 5cm F1.5, uncoated optics, wide-open on the Leica M Monochrom
1936 Carl Zeiss Jena 5cm F1.5, uncoated optics, wide-open on the Leica M Monochrom
Coated and uncoated Sonnars were produced concurrently starting in 1936.
Coated and uncoated Sonnars were produced concurrently starting in 1936.

In conclusion

Sonnars render images differently due to their asymmetric design. The uncoated Sonnars have less contrast and muted colors compared to their coated counterparts. The 90-year-old design is not as sharp as the modern C Sonnar. Some work is required to adapt them to Leica mount. They are not for everyone, but if you want a classic look that’s hard to capture — they might be for you.

Skyllaney is now offering a professional service to convert the pre-war Sonnars to Leica mount. I am happy to have a professional shop to refer people to.

You can read more about Sonnar lenses on 35mmc here
And read about Hamish’s search for the perfect classic Sonnar here

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27 thoughts on “Zeiss Jena 5cm Sonnars – The Magic of the Prewar Uncoated Sonnar – By Brian Sweeney”

  1. Great read but I wish people reviewing lenses would do some shots at a normal f8 aperture rather than always wide open.



    1. This is not a formal review, but one designed to answer a question “what makes a Sonnar different from other lenses?” that was posted in response to the Skyllaney announcement.

  2. PITA to find and used. A solution is the much less expensive Russian Jupiter 3 (f1.5) and Jupiter 8 (f2) which are war reparation clones of the Sonnars. Spotty QC, but if you get a good one that RF synchs correctly, it is very good. Also works well with live view.
    The early Nikkor and Canon RF lenses were minimal tweaks of the Sonnars but obtained irregularly (some would say illegally) since Japan was most definitely NOT at war with Germany …

    1. The Nikkor-SC 5cm F1.5 was designed in 1937. German optical engineers collaborated with Japan before the war. The Canon 50/1.5 is very good, but the lubricants used could damage the rear triplet. It is optimized for F2.8. Be sure to be able to inspect and have return privilege.
      I’ve probably adjusted some 200 Jupiters for Leica, they can be cans-of-worms. I used to do this for RFF members. I have two 1950 KMZ J-3’s with Zeiss serial numbers that have perfect glass. That’s because no one could use them, the spacing between elements was wrong. That took a lot of work to get right. I’ve written procedures for adjusting Jupiter-3’s.



      Not the worst That I’ve seen, but required removing all the glass and soaking in acetone for 4 days to get the optics module out so the lens could be shimmed.


  3. Thanks for this Brian. It’s delightful to read you again. And those wonderful images with the Sonnar.

    I am afraid this article is going to drive up the prices again 🙂

    1. I’m glad my Sonnar collection is complete… I took a look at CZJ 5cm F1.5 Sonnars in Contax mount on Ebay- more than double of what I used to find them at.

      I’ve converted 50 pre-war 5cm F1.5 Sonnars to Leica mount, and 10 5cm f2 Sonnars to Leica mount. Of those- I own 7 myself. I’m glad to see Skyllaney now performing these conversions, and doing it right. I am officially retired from it!

  4. I love this level of analysis. I’m not at all a lens geek and use the word geek to mean reverence to those who are true experts rather than just someone who is ultra picky about details which don’t matter.
    I’ve never come across a better explanation about focus shift. I even had one from Zeiss which didn’t properly explain it.
    I have two Zeiss Sonnar 50 1.5’s one a post war on a Contax iia the other a ZM on a Leica M2. I’m not analytical. I like them for what they are and just like Zeiss lenses. I generally use later designs on later cameras, Contax G, Contax RTS and 645 etc so more Planar, Biogon Distagon. I do have Sonnar 100 and 135 for the C/y mount as well as a 90G so am curious as to whether they have a similar mystique according to your good self

    1. Jeremy, Thankyou.

      I’ve not shot with the the C/Y Sonnars, or the 90/2.8 Sonnar- and just looked up the formula for each. Bertele designed the Ernostar before the Sonnar. For the latter, he used low-index of refraction glass to eliminate the air/glass surfaces between the second and third element. If Bertele had modern multi-coated optics, he probably would not have done so. Your three lenses follow Bertele’s original Ernostar design, as does the Leica M-Mount C-Sonnar 50/1.5. As the company merged with Zeiss- the Sonnar name is very fitting on these lenses. I have the C-Sonnar, it lives up to the name- as do yours. I also converted a 13.5cm F4 Carl Zeiss Jena Sonnar to Leica mount-


      The Great-Grandfather of your lenses.

    2. I have a 1934 50mm 1.5 Sonnar that came with a broken Contax I. The lens is fantastic And I use on my M’s via adaptor. I have someone interested in buying it, but I have no idea the value of the original black enamel/nickel version I have. Anyone have any idea?

      1. Prices are up compared with when I was buying these lenses. 1934 marked a change in construction. Does you lens have filter threads, or is it made for using with push-on filters only? The lenses with threads are easily converted to Leica mount using a Jupiter-3 focus mount. The early version must be used with an adapter, as you are doing. Ten years ago- $150 got a very pretty one. The one I show in this article was $76- but the glass looked like wax paper when received. It had never been opened, cleaned up perfectly. The J-3 mount, made from 3 parts lenses. Prices for the pre-war 5cm F1.5 Sonnar seem to have shot up past the $300 mark, and exact price depends on condition of the glass and condition of the cosmetics.

        1. Mine has the push on filter, no threads. I’ll probably hang onto it unless it commanded crazy prices. It’s rare and TINY, which are both a plus in my book. Thanks for the quick reply!

          1. I would keep it as well. Like my wife told me, “If you use it, keep it. If you like it, Keep it. If you do not like it and do not use it, then sell it.”

  5. It strikes me that your explanation of the impact of the asymmetric design of the Sonnar is also relevant to the design of the Tessar which is similar, if optically slower. This explains the Look I have gotten on Tessars for LF, MF and 35mm.

    Now hopefully prices will remain sane for me 🙂

  6. Very nice article Brian. I completely agree with your analysis on why the Sonnar’s render magically.

    I also have shared your adventures trying to find good copies of these lenses from the pre and post war era’s, I’ve been scouring the used market for several years now, and they are slowly becoming less and less available, and the ones available, more and more expensive over time. I’m still searching for the earliest Nickel version (first 600 ever made), which remains elusive to me.

    Regards the bloom, I’m actually very glad you said it helps with the colours.
    I have a 5cm f/2 Jena that is so ‘bloomed’ Ive been dabbling with Cerium Oxide and polishing machines to actually remove it. Now, I’m tempted to leave it there if you said it helps the colours.

    I have noticed that certain Jena Sonnars seem to make absolutely lovely vintage colours, my favourites seem to be the very early T coated ones (300 series serial numbers), in the collapsible mounts for Contax cameras. Anytime it’s sunny here in England (this is rare, but it does sometimes happen), and I’m going to go outside to photography the greenery, I take a Sonnar. They seem to excel at this colourful 3D image capturing, comets and all 🙂

    1. Thankyou for the reassuring words. I had to look up the 300 block in Thiele, the block was finished in 1947- some of the first lenses finished after WW-II. I have a 270 block 5cm F2 Sonnar T, block finished in 1944. Part of the welcoming committee for the Bertele 50/2. The 1607 block 5cm F1.5 used in the article is the earliest that I’ve seen that has threads compatible with the J-3. It from a black-striped fixture, Contax I vintage. Of course the conversion is reversible, So I kept the original shims and Contax mount intact. My 175 block 1935 lens switched over to chrome finish and dropped the black stripe. But- the front element is coated, I’ve seen one other like it.

      With your business- you will be handling a lot of Sonnars! The small changes are worth noting, were introduced without fanfare and were not written down in the books.

  7. A great read and very educational for me, thank you both. I’m very much a Sonnar novice with only a J3 and 8M in my possession. Curious as to why Skyllaney are not working with the f1.5 Sonnars and only the f2?

    1. Paul, Thankyou. I don’t know the factors that went into the Skyllaney decision to produce produce the 50/2 Sonnar formula lens. There are currently two Sonnar formula 50mm F1.5 lenses in production: the Zeiss 50/1.5 C-Sonnar and the Zenit/Lomography Jupiter-3+. They are both beautiful lenses, I have both of these. The original 5cm F1.5 Sonnars used hard glass for the front element, and finding them in good condition is fairly easy. The 50/2 used soft glass, finding a clean one is difficult. Bringing out a 50/2 Sonnar formula lens with modern coatings makes the Skyllaney Bertele lens unique, the first new incarnation in 65 years. As far as I know, The last time a company brought out a new incarnation of the classic 1-3-2 50/2 Sonnar for the Leica was the Tanar 5cm F2 of 1955. Another lens in the my welcoming committee when the Bertele 50/2 arrives.

      1. Brian pretty much nailed it on the head as to why we did the 5cm f/2 formula instead of the faster f/1.5 formula. Both Lomography and Zeiss have released modern incarnations of the faster 1.5 formula in the last decade or two.

        The slower f/2 formula hasnt been visited since the post war/ 1950’s and 60’s era.

        Also, no native M mount version exists for the f/2 variant, and myself, Hamish and some others have found that the f/2 version renders smoother bokeh vs the f/1.5 variant at like for like apertures.

        I do own the Zeiss ZM 50mm f/1.5 Sonnar, and optically feel it is excellent. If I were to resurrect the original 1930’s f/1.5 sonnar formula, I do not feel I could have done a masterful job as Zeiss and Cosina did with the ZM C-Sonnar, optically.

        For us (Skyllaney), we felt the f/1.5 already had its modern M mount incarnation (ZM C-Sonnar), so we instead focused on its long forgotten (slower but smoother) brother.

        I’ve always been partial to the slower brother myself.

  8. This is awesome, very educational thank you.

    In terms of colours – since there are so many factors (film stock, scanning etc) how much is it possible to attribute to a lens?

    1. The rendering of lenses was traditionally described as “Warm” or “Cold” with regard to color cast. In the 70s, Nikon was known for their “Nikon Integrated Coating” which was reputed to equalize color rendering across their range of lenses. When shooting slide film, as opposed to color negative film- it was easier to pick up on subtle differences between lenses. These days- shooting with a digital camera brings out differences between lenses. The color filter array is invariant, makes it much easier to pick up on the differences being introduced by the lens.

      This thread is a good example, compares multiple 50/1.5 Sonnar formula lenses on the M9. One of the few times that I drag a heavy tripod out for an informal lens test.


      I’ll be doing some tests like the above when the new Skyllaney lens gets into my hands.

  9. Pingback: Skyllaney Rehoused 1930s Uncoated Zeiss Jena 50mm f/2 Sonnar

  10. I’m another that likes the f2 version very much. Mine (early collapsible version, in chrome) seems to have almost flawless glass: I didn’t know this was hard to find until long after I had found it, for a pittance, in a camera shop’s odds and ends drawer some time in the 1980s. I don’t seem to get lucky on the great lens hunt very often, but that day I did.

    1. I also got lucky a long time ago with this lens- found on a Nikon M in an Antique store. Went back a month later, found a second Nikon M with an early 5cm F1.4 on it.

  11. Hey Brian,

    I have a Jupiter 8m that I would like shimmed (I have a canon p) and I was curious if you still do these? If not, no problem. You are the consensus great online, however I have not found your contact info anywhere. I apologize for using the comment section for this request, but if you still work on Jupiter 8’s and would be interested, my email is [email protected]. Thanks!

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