TenEleven's Zeiss Contax (I, II, IIa) Lens Compendium

Sadly, I'm at the character limit for the first post. I will however make another post and then maybe that can be moved below the first one?

We will work out something to make it coherent.

The amount of info you have shared so far is fantastic
-- more lenses would be even better.

I am a fan of the 50/1.5 all versions, 40/2, 180 all versions, 500

Thanks,
Stephen
 
Wartime Jena 35/2.8 Biogon - Rangefinder Coupled - Does NOT mount on IIa - (4 groups / 6 elements)
Usually coated. Rare. Similar to the uncoated pre-war Biogon, but with better contrast. All copies of these lenses seem to fall into the 2.6xx.xxx serial number range and usually in aluminum finish. Focus does not feel as smooth as their brass contemporaries, but they are about 70grams lighter. (5.3oz vs 8.1oz) Unlike their their un-coated brethren highlights do not spread out as easily, color reproduction is good.

Finder: See 35mm Biogon entry.

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Post-war Jena 35/2.8 Biogon - Rangefinder Coupled - Does NOT mount on IIa - (4 groups / 6 elements)
All coated. Rare. Similar to the coated and un-coated pre-war Biogons. All copies of these lenses seem to fall into the 3.xxx.xxx serial number range and are exclusively in aluminum finish. Fit and finish is slightly reduced, however the optical formula appears to have been tweaked (new glass types?) central acutance is extremely high, akin to a good sample of a Jupiter-12.

Finder: See 35mm Biogon entry.

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Pre-war Nickel Jena 50/2.0 Sonnar - Rigid - Rangefinder coupled - Mounts on IIa - (3 groups / 6 elements)
All uncoated. Rare. Nickel and brass finish. Two optical variants. Many variations in appearance and aperture mechanism. The rear doublet has been enlarged from 19mm to 23 ~ 24mm diameter. Interestingly the first - "narrower" version has very slightly better corner performance, but has bought this extra performance with more vignetting that disappears by f/5.6. The later version is identical in signature to the collapsible lens, but often out-resolves its collapsible contemporaries in the field; most likely due to improved mechanical stability afforded by the lack of a collapsing mechanism.

Finder N/A

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War-time Jena 50/1.5 Sonnar - Rangefinder coupled - Mounts on IIa - (3 groups / 7 elements ?)
Most coated. Rare. Serial number ranges from 2.6-2.8xx.xxx. Usually aluminum finish, but partial or full brass versions are seen. Two known copies have click stops. A first and perhaps special issue version. Central resolution appears extremely high, spherical aberration is almost absent, but both seem to have been "bought" with a considerable increase in linear distortion. (barrel type, another rarity for Sonnars) Perhaps an experimental branch of the Sonnar family tree.

Finder N/A

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Post-war Early Carl Zeiss Opton 50/1.5 Sonnar - Rangefinder coupled - Mounts on IIa - (3 groups / 7 elements)
All coated. Relatively rare. Samples as early as 69.xxx serial have been seen. Brass finish. Identifiable by having a silver - not black filter mounting ring. Often referred to as "silvernose" Sonnar. Optically the first versions represent a unique batch that has a slightly different signature than later Opton "blacknose" Sonnars. The rear group is taller, most likely due to different glasses or computations being used. The front singlet is mounted into its own brass washer making these lenses slightly (~20g) heavier. The depiction is, perhaps not unexpectedly, in-between the pre-war variant and the later Carl Zeiss Sonnars. Contrast is high, but spherical aberration is not as well controlled as either earlier or later samples - robbing some resolution at full aperture. The acutance does however improve very quickly upon stopping down.

Finder N/A


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Post-war Jena 50/2.0 Sonnar Rigid - Rangefinder coupled - Mounts on IIa - (3 groups / 6 elements)
All coated. Somewhat common. Serial range from 3.xxx.xxx. Aluminum finish. An interesting evolution on the Sonnar design and also, even more interestingly together with the f/1.5 variant it represents a "dead end" in the Sonnar family tree. This lens optical design has been re-worked and the rear-lens-group diameter has once again been increased to ~25mm. It offers very good performance at open aperture already with reduced vignetting. By f/4 this lens already offers excellent all-round performance, however with lowered contrast and a cooler color palette compared to its post-war western "Opton" brothers. Many of these lenses also have the rear section of the mount coated in black to help prevent internal reflections.
This lens represents a dead-end in the Sonnar family tree, as the optical elements can not be exchanged into a post-war or pre-war mount of either Sonnar, nor will the lenses fit the appropriate Jupiter mount, which is based on the pre-war measurements of the same lens.



Finder N/A

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Post-war Jena 50/3.5 Tessar Collapsible - Rangefinder coupled - Mounts on IIa - (3 groups / 4 elements)
All coated. Somewhat rare. Serial range from 3.xxx.xxx. Aluminum finish. A re-thread on the budget pre-war lens with some optical tweaks worked into the formula making it perform a bit closer to its excellent and highly-sought after rigid western contemporary Tessar. Like the Opton/Carl Zeiss variant this variant was meant to be used on the Contaprox close-up attachment and can sometimes still be found with these. Perhaps due to concessions allow the lens to collapse, the field contrast and resolution at full aperture are slightly lessened compared to its rigid western brother. It does however offer very solid performance and flare resistance at any aperture.

Finder N/A

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Post-war Carl Zeiss (Opton) Sonnar 85/2.0 - Mounts on IIa - (3 groups / 7 elements)
All coated. Uncommon. Aluminum finish with custom barrel design. The original - perfected. This lens takes the few remaining caveats of the above lens and corrects them. As Marco Cavinia attests: The later Opton version is one of the best 85s made for any rangefinder system. Sharp from wide open with lots of contrast and a depiction that only gets better as you stop down. Usable at any focal distance from wide open. Some flare can be seen. No distortion. Focuses down to 1.0 meters.
Due to the synthetic optical cement used the later "Carl Zeiss" labeled versions of this lens are very prone to lens cement failure.

Finder - see Sonnar 85.

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Post-war Jena Sonnar 85/2.0 - Mounts on IIa - (3 groups / 7 elements)
All coated. Somewhat common. 3.xxx.xxx Serial number range. Aluminum finish, but different barrel from the Opton variant. This lens reflects a change made to the original (heavy) pre-war Sonnar around 2.6xx.xxx when a seventh lens element was introduced into the rear group making the design akin to the 50/1.5 Sonnar. It is relatively sharp from wide open with medium contrast most stemming from the "civilianized" coatings, which are different both in appearance and transmission to the war-time 'T' coatings. Like its pre-war predecessor it does not "like" being shot at infinity at full aperture and unusual falloff can be seen in the field, most likely due to field curvature. However by stopping down to even ~f/2.4 the issue is resolved. Some flare can be seen. No distortion. Focuses down to 1.25 meters. Unlike it's "Opton" western contemporaries, this lens does not usually suffer from cement failure.

Finder - see Sonnar 85.

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Pre-war Jena Tessar 135/4.5 - Mounts on IIa - (3 groups / 4 elements)
Most uncoated. Uncommon. Brass finish. Heavy. The longest "practical" lens on the Contax system. Good sharpness from wide open that is somewhat hindered by this lenses relatively low contrast, made worse by the lack of coatings. This lens is also one of the most flare prone listed here and a hood is an absolute must. There is no distortion. Excellent landscape performance by f/8. Unlike some of its contemporaries this lens does not mind at all being shot at infinity at full aperture. Focuses down to 1.5meters.

Finder - the torpedo finder can be used referencing the drawn frame-lines making for a decent but not great view. The Contax II clip-on finder may be also used but we're getting into squinty territory. Again modern alternatives fare better here.
 
I've removed the post-war 85 from the top post and moved it to the bottom post, breaking down the various versions a bit more. I've also amended some information to the post-war 50/2.0 Sonnar and added information about the materials and weight where sensible.


There's also an entire can of worms waiting to be opened on Zeiss 'T' coatings. I have observed at least four variants in the field:


COATINGS



First (Initial) version
Most likely a dip-and dunk process as opposed to a vacuum process. The coating is uneven and splotchy (even for internal surfaces meaning that it is not likely due to wiping/ageing processes) with sometimes even tiny droplet patterns visible. Compared to an uncoated lens the transmission is slightly increased, however not as much as later processes. The coating does appear as a very faint light-blue sheen - and is best seen in artificial light. It does seem to rub off with intense cleaning revealing the uncoated glass surface underneath again pointing to a possible dip and dunk process. Samples as early as 1.4xx.xxx have been seen with this coating. They are not marked as 'T' coated, nor is there references to a "Transparent" process. However, specimens with a drilled out dot filled with red paint exist. The uniformity of the coating across various Contax lenses and eras (and not for other mounts!) does point to this being a Zeiss process and not a 3rd party.


Second version
These lenses are either military issue war-time lenses, or have been sold to neutral countries also during the war time. Usually labelled with a red 'T', but variants with a drilled out dot filled with red exist. The coating does have the usual Zeiss hues of orange/brown with a violet/blue secondary tone. The coating is usually very evenly applied to the entire lens surface and wipe and drop marks are usually not seen. There may be pin-prick size smaller anomalies of unknown origin. The coating appears to be relatively hard and persistent and will not wipe off even with intense cleaning. The transmission of light is greatly increased compared to an uncoated lens, and again increased to a lens coated with the first process. It seems to have first appeared around the 2.56x.xxx serial number range. Some of these lenses were specifically noted as "Verg." meaning "Verguetet" aka coated on their lens production card.


Third version
Commonly seen on the immediate post-war Carl Zeiss Jena lenses. All are labelled with a red 'T'. The coating reverts to a look similar but not identical to the first version of the coatings with a deep blue base-color with only very very subtle hues of other colors visible in oblique light. Compared to an uncoated lens transmission is greatly increased, and still noticeably increased compared to the first process version. However, transmission appears to be slightly less(!) than the second - war-time - version. The coating is hard and repeated cleaning will not rub it off. There are no marks or splotches to be seen and the application is perfectly even. Serial numbers are from 2.9xx.xxx and up.
A theory for this coatings existence is that the occupying Russian force might have declared the original 'T' coating a secret for their own uses. This is however speculation.


Fourth version
Commonly seen on post-war western (Opton) Zeiss lenses. Most are labelled with a red 'T', however variants with a white character resembling an 'F' have been seen. The coating looks most similar to the second war-time version of the coatings with violet/orange and brown hues alternating depending on the angle of view. The transmission of light is the greatest of all coatings listed here. The application is perfectly even and the coating does appear to be very hard with even deeper scratches being unable to dislocate it.
Most likely western Germany Zeiss could use the war-time coating technology as they were not under Russian jurisdiction. This is again however speculation.
 
There are also post-war Jena 5cm f2 and f1.5 lenses that are not part of the list yet.
I just got an f2 variant (sending it back since the leica adapter it's mounted in is in bad condition), which is made from a light aluminium alloy and has many bubbles in the glass (not worried about those).
 
There are also post-war Jena 5cm f2 and f1.5 lenses that are not part of the list yet.
I just got an f2 variant (sending it back since the leica adapter it's mounted in is in bad condition), which is made from a light aluminium alloy and has many bubbles in the glass (not worried about those).


Yes I am aware of this version.

I can in fact tell you that the optical formula for both has indeed been reworked and it sort of represents a 3rd branch (the original and the western "Opton" variants are the other) in the Sonnar tree. It is a sort of dead end as, very puzzlingly, judging from glass diameters, mount mechanisms and screw-thread measurements etc. the Jupiter lenses appear to be based on the pre-war and war-time variants of the lenses - NOT the post war Jena ones, a progression that would have made more logical sense...

I can do a write up for the 2.0 version, but the 1.5 version I've only seen two samples so far - one of which I have in LTM which does not really feel sufficient for me to write confidently about this lens.
 
I've removed the post-war 85 from the top post and moved it to the bottom post, breaking down the various versions a bit more. I've also amended some information to the post-war 50/2.0 Sonnar and added information about the materials and weight where sensible.


There's also an entire can of worms waiting to be opened on Zeiss 'T' coatings. I have observed at least four variants in the field:


COATINGS



First (Initial) version
Most likely a dip-and dunk process as opposed to a vacuum process. The coating is uneven and splotchy (even for internal surfaces meaning that it is not likely due to wiping/ageing processes) with sometimes even tiny droplet patterns visible. Compared to an uncoated lens the transmission is slightly increased, however not as much as later processes. The coating does appear as a very faint light-blue sheen - and is best seen in artificial light. It does seem to rub off with intense cleaning revealing the uncoated glass surface underneath again pointing to a possible dip and dunk process. Samples as early as 1.4xx.xxx have been seen with this coating. They are not marked as 'T' coated, nor is there references to a "Transparent" process. However, specimens with a drilled out dot filled with red paint exist. The uniformity of the coating across various Contax lenses and eras (and not for other mounts!) does point to this being a Zeiss process and not a 3rd party.


Second version
These lenses are either military issue war-time lenses, or have been sold to neutral countries also during the war time. Usually labelled with a red 'T', but variants with a drilled out dot filled with red exist. The coating does have the usual Zeiss hues of orange/brown with a violet/blue secondary tone. The coating is usually very evenly applied to the entire lens surface and wipe and drop marks are usually not seen. There may be pin-prick size smaller anomalies of unknown origin. The coating appears to be relatively hard and persistent and will not wipe off even with intense cleaning. The transmission of light is greatly increased compared to an uncoated lens, and again increased to a lens coated with the first process. It seems to have first appeared around the 2.56x.xxx serial number range. Some of these lenses were specifically noted as "Verg." meaning "Verguetet" aka coated on their lens production card.


Third version
Commonly seen on the immediate post-war Carl Zeiss Jena lenses. All are labelled with a red 'T'. The coating reverts to a look similar but not identical to the first version of the coatings with a deep blue base-color with only very very subtle hues of other colors visible in oblique light. Compared to an uncoated lens transmission is greatly increased, and still noticeably increased compared to the first process version. However, transmission appears to be slightly less(!) than the second - war-time - version. The coating is hard and repeated cleaning will not rub it off. There are no marks or splotches to be seen and the application is perfectly even. Serial numbers are from 2.9xx.xxx and up.
A theory for this coatings existence is that the occupying Russian force might have declared the original 'T' coating a secret for their own uses. This is however speculation.


Fourth version
Commonly seen on post-war western (Opton) Zeiss lenses. Most are labelled with a red 'T', however variants with a white character resembling an 'F' have been seen. The coating looks most similar to the second war-time version of the coatings with violet/orange and brown hues alternating depending on the angle of view. The transmission of light is the greatest of all coatings listed here. The application is perfectly even and the coating does appear to be very hard with even deeper scratches being unable to dislocate it.
Most likely western Germany Zeiss could use the war-time coating technology as they were not under Russian jurisdiction. This is again however speculation.

More good information. Thanks! Do you know when the various coatings were applied (roughly)?

I know there is some uncertainty on the post war [Carl Zeiss; Zeiss Optron; maybe others] 35mm f2.8 Biogon. Mine is a "Carl Zeiss", and has no "T" or other extra symbol on it, but I understand these are coated.

I think Zeiss started some coating as early as the late 1930s, but only for military customers?
 
I have an 18 cm f/6.3 Tele Tessar K that I have used on my Contax bodies. In bright sunlight with Tri-X the f/6.3 aperture isn't a problem and I have found it to be a reasonably good performer. I always use it with a fairly deep lens shade but haven't found it to be particularly flare prone. Finding a shade was a bit of an adventure since mine seems to be something of a transitional lens with no front filter threads and what might be nickel finish with a black band between the f/stop ring and the front of the lens. I eventually found a clamp on filter attachment with 46 mm threads and then got a 46 mm hood to go on that. The finish on the body of the lens looks a lot "warmer" than the chromed brass 135 and 85 Sonnars that I have, but that could be a variation in the chrome--not my area of expertise or experience.
 
More good information. Thanks! Do you know when the various coatings were applied (roughly)?

I know there is some uncertainty on the post war [Carl Zeiss; Zeiss Optron; maybe others] 35mm f2.8 Biogon. Mine is a "Carl Zeiss", and has no "T" or other extra symbol on it, but I understand these are coated.

I think Zeiss started some coating as early as the late 1930s, but only for military customers?


It's hard to say when they started coating stuff. I've seen stuff as early as 1.5million serial coated with their first iteration of coatings - that would be around 1936 so yeah your late 1930s guess is most likely correct. However -- the big question remains: did it come like that out of the factory, or could customers send in the lenses they liked and have them coated later on?

Regarding the military and the state-secret there is some uncertainty whether that applied to all of Zeiss' coatings or just the much more effective 'T' or 'Transparent' vacuum-deposit coating process. As noted earlier the other coating is applied differently, is softer and not as effective. So, sadly all I can offer here is speculation.

At least I can definitely answer your last question:
Carl Zeiss along with other makers simply dropped the 'T' mark around the same time they switched from 'Opton' to just 'Carl Zeiss' after winning the legal battle for the trademark with Jena.
This was done alongside other manufacturers as lens coatings had become commonplace and it was no longer something that set one lens maker apart from another.

I guess, they re-introduced it for marketing purposes with their improved T* coatings, but that's another story...

I have an 18 cm f/6.3 Tele Tessar K that I have used on my Contax bodies. In bright sunlight with Tri-X the f/6.3 aperture isn't a problem and I have found it to be a reasonably good performer. I always use it with a fairly deep lens shade but haven't found it to be particularly flare prone. Finding a shade was a bit of an adventure since mine seems to be something of a transitional lens with no front filter threads and what might be nickel finish with a black band between the f/stop ring and the front of the lens. I eventually found a clamp on filter attachment with 46 mm threads and then got a 46 mm hood to go on that. The finish on the body of the lens looks a lot "warmer" than the chromed brass 135 and 85 Sonnars that I have, but that could be a variation in the chrome--not my area of expertise or experience.

That's pretty cool info - thanks for that. Hows the picture rendition of that lens? Is it rangefinder coupled at all?
 
Yes, it is rangefinder coupled and focus is accurate on Contax II and IIa bodies. As you would expect, this isn't the most high contrast lens but it is reasonably sharp. I haven't shot color film with it so I can't comment on color rendering. The limiting factor on sharpness may be the fact that I have mostly used this lens hand held rather than on a tripod, although I am careful to shoot at at least 1/250 or higher and to hold the camera carefully. For a viewfinder I use a Zeiss pre war 436/7 finder with the 18 cm lens. It isn't an SLR but I have found it to be reasonably accurate and easy to see the full frame. One discovery that I have made with these finders is the unscrewing the rear lens slightly is essentially diopter control, so that I don't need my glasses to see a sharp image for framing.
 
I am attaching a quick photo of the 18 cm Tele Tessar K on a Contax II with an 8.5 cm f/2 brass/chrome Sonnar. I don't think the color difference between the two lens barrels shows up quite as well in the picture as it does to the eye, but there is some difference in the sheen and I think that comes across.
 

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This is a wonderfully informative thread. Thanks for posting your findings, TenEleven. I'll be bookmarking this later. I'm now also regretting selling my "dead-end" post-war f2 Sonnar as I didn't know that it was a bit of a unique variant in the line up...
 
I have one lens in chrome and one lens in Nickel/Black. Is there an optical difference between these two lenses?

Pre-war Jena Tessar 50/2.8 - Mounts on IIa - (3 groups / 4 elements)
Rarely coated. Common. Brass finish. Designed to be the second-cheapest 50 for the system. The optical price for speeding up the Tessar design proved a bit much. It is not a bad lens per-say but the flare and vignetting performance is a bit worse than its slower brother. This is especially true for flare which hits the larger front element easily. However, by f/8 the differences to its' slower brother are completely negligible.

Finder N/
 
Thank you to the OP for this thread. It’s wonderful to have this information in one place. I got into the Contax RF system several years ago and now find myself fortunate to have five of the lenses reviewed here: (1) wartime 5cm f1.5 Sonnar; (2) post-war 5cm f1.5 Sonnar; (3) post-war 5cm f2.0 Sonnar; pre-war (and uncoated) 8.5cm f2.0 Sonnar; and a post-war 35mm f2.8 Biogon. The Biogon and the two post-war Sonnars in particular are fantastic lenses; and the Sonnars can be used on M-mount and LTM cameras via adapters.

Here are a few pics…

Post-war 5cm f1.5 Sonnar:

Rio di Sant’Angelo by Steve Macfarlane, on Flickr

Post-war 5cm f2.0 Sonnar:

Sierra Columbine by Steve Macfarlane, on Flickr

Wartime 5cm f1.5 Sonnar:

Listening by Steve Macfarlane, on Flickr

Post-war 35mm f2.8 Biogon:

The Riders by Steve Macfarlane, on Flickr

Although the photos above are all black and white, I think the Biogon and post-war 5cm f2.0 Sonnar do beautifully well with color film.
 
I have one lens in chrome and one lens in Nickel/Black. Is there an optical difference between these two lenses?

Pre-war Jena Tessar 50/2.8 - Mounts on IIa - (3 groups / 4 elements)
Rarely coated. Common. Brass finish. Designed to be the second-cheapest 50 for the system. The optical price for speeding up the Tessar design proved a bit much. It is not a bad lens per-say but the flare and vignetting performance is a bit worse than its slower brother. This is especially true for flare which hits the larger front element easily. However, by f/8 the differences to its' slower brother are completely negligible.

Finder N/

I have updated the first post to add more information on this lens and also added additional lenses.

Regarding your inquiry, sadly I only have second-hand information on the Black & Nickel version of this lens, but from what I heard it performs nearly identical. I think Zeiss spent most of their effort (and re-computations / tweaks) on the stars of the show, so to speak. Beware that this lens has quite strong focus shift, even more than the Sonnar!

The 3.5 version is free from said focus shift.
 
I have updated the first post to add more information on this lens and also added additional lenses.

Regarding your inquiry, sadly I only have second-hand information on the Black & Nickel version of this lens, but from what I heard it performs nearly identical. I think Zeiss spent most of their effort (and re-computations / tweaks) on the stars of the show, so to speak. Beware that this lens has quite strong focus shift, even more than the Sonnar!

The 3.5 version is free from said focus shift.

I have seen the Nickel version often listed with a Contax I, suggesting that it was older than the chrome version which may be associated with Contaxt II.
 
I have several Zeiss lenses that either are still in Contax mount or that Brian has converted to ltm or M mount. Of course, the 5cm 1.5 is one of the favorites, but the 50 2 is no slouch. The 50 2.8 Dresden is a beautiful lens that may be better suited as an occasional portrait lens. I also have a Tessar 5cm 3.5 that I do not recall to have used so far. [I know that we want to keep this thread on Zeiss lenses, so I will not bring up FSU lenses made for the Contax]
 
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Contax IIa with Zeiss Sonnar 5cm 2.

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I used Contax rangefinders for a couple decades until I switched over to Leica. I'd post what I know but at some point I think I'd like to get the lenses I used to have again, so I don't want to inflate the prices of them...

All the 50 Sonnars I owned were good. The f/2 versions were no slouch. IMO unless you are going to shoot at night, just get an f/2. I can't remember what post war versions of that I had though. The prewar f/2 collapsible was a nice lens for what it was. Wasn't too sharp, had a little flare but overall made nice images. A perfect lens if you want that vintagey look. I remember owning both the Carl Zeiss and the Opton versions of the 1.5 Sonnar. I don't remember there being any difference frankly. The only lens I still have is the pre war 1.5 Sonnar that I like too much to sell since the glass is good and the lens looks like crap. Nice and sharp without tons of contrast. And I kept one old IIIa body that was hammered but works perfectly.

I have tons of pictures shot with the Contaxes that I could post, but unfortunately back then I never kept track of what lens was used for what so I don't know what good it would do in this context.

Thanks for starting the thread though. Makes me want to get some Zeiss glass again.
 
Carl Zeiss Jena Orthometar 1:4.5 f=3.5cm on Zeiss Ikon Contax IIIa camera with 432/5 35mm viewfinder
 

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Carl Zeiss Biogon 1:4.5 f=21mm on Zeiss Ikon Contax IIIa camera with 435 21mm viewfinder
 

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