Data sheet: Carl Zeiss (C/Y) Distagon 28 mm f/2.8

Pekka Buttler, 01/2023

Specifications

The table below summarizes the lens’ key specifications (Measurements based on pictured sample):

Brand:	Carl Zeiss	Lens name	Distagon 2,8/28
Focal length(s) 1	28 mm	Angle-of-view 2	74 °
Maximum Aperture	f/2.8	In Production	1976–≈2000
Lens mounts	Contax/Yashica	Subfamily (if applicable)	––
Length 3	50,3 mm	Diameter 4	63,4 mm
Filter ring diameter	55 mm	Weight	281 grams
Lens element count	7	Lens group count	7
Aperture blades (S/R/C) 5	6 S	Focus throw	120 °
Minimum focusing distance	25 cms	Maximum magnification	1:6,8
Has manual aperture ring	YES	Has Manual focus ring	YES
Aperture mechanism type	Automatic	Aperture click stops 6	2.8-4-5.6-8-11-16-22

Further notes:
• This lens is the slower of two 28 mm focal length lenses designed by Zeiss for the Contax/Yashica system.
• Zeiss/Yashica offered two approaches to shielding this lens’ front element against sunlight:
• The Soft Lens Shade 55mm G-12 is a thread-mounted rubber lens hood
• You could use a combination of the 55/86 screw-in ring and Metal Lens Hood No.1
• Neither approach supports using filters and lens hood (hard vignetting may occur).
• Alternatively, you can use any aftermarket wide-angle -length 55 mm thread lens hood.

Versions

The Carl Zeiss Distagon 28/2.8 for the Contax/Yashica mount was manufactured in two nominally different versions:
• AE, made in Japan (1976–1984)
• MM, made in Japan (1985–≈2000)
(for information of the significance of these, read on)

Adapting

This lens cannot be used natively on any current SLR or dSLRs. To use it in its native environment, you will need a Contax or Yashica body with a Contax/Yashica mount. Luckily these are quite easy to find, and Yashica’s manufacture of the electronics has been relatively resilient to the teeth of time.

Thanks to being a fully manual lens (manual aperture, manual focus), the lens can be adapted to all mirrorless cameras using a suitable adapter. Moreover, a simple ‘dumb adapter’ will do the job perfectly. Thanks to the popularity of the C/Y mount, the availability of adapters to all mirrorless mounts can be taken for granted, on the other hand, specialist adapters (speed boosters, helicoid adapters, tilt/shift adapters) are not available for all mirrorless mounts, but daisy-chaining adapters (e.g. C/Y->Canon EF; Canon EF –> mirrorless) can offer a work-around.

Using C/Y mount lenses on dSLRs can also be an option, depending on which dSLR.
• Canon EF has the shortest flange focal distance among full-frame dSLR’s and Canon’s wide range of dSLRs are able to mount C/Y lenses perfectly using a simple adapter ring.
• Sony/Minolta A, Pentax K and Nikon F dSLRs are not able to use C/Y lenses without an adapter that uses corrective optics to allow infinity focus. However, such adapters are readily available.

History of Carl Zeiss (Oberkochen)

There are few names in camera optics more illustrious than that of Carl Zeiss. Founded in the German town of Jena in 1846 by Carl Zeiss (hence: ‘Carl Zeiss Jena‘), there are few major developments in lens optics that the company was not involved in during 1846–1945. Names that are even today well-known in optics – such as Planar (1896), Tessar (1902), Sonnar (1929), and Biotar (1939) – were the product of Zeiss’ first century of technological innovation. But as the second world war broke out in 1939, development of consumer optics had to take the back burner…

After the Second World War Germany was divided into a Soviet zone (subsequently: East Germany) and the west-allied zones (subsequently: West Germany). While most Zeiss works resided in Jena (optics and glasses) and Dresden (cameras), which were in the Soviet sector, a contingent of Zeiss managers migrated to a Zeiss plant in Oberkochen near Stuttgart (American Zone) and set up shop in the West under the name of Opton Optische Werke Oberkochen GmbH. As the relations between the former allied deteriorated and the split into East and West Germany became all the more real, the Oberkochen works changed their name first to Zeiss-Opton and later to Carl Zeiss.

What ensued was a lengthy international trademark dispute with both Zeiss’ (Jena and Oberkochen) laying claim to the name ‘Carl Zeiss’. The resulting stalemate – emblematic of the Cold War in its entirety – resulted in that Carl Zeiss Opton was allowed to use the name Carl Zeiss in the West, but had to use the Opton brand in the East bloc, whereas Carl Zeiss Jena was the only real Carl Zeiss as far as the east bloc was concerned, but could – mostly – not use the Carl Zeiss -name for exports to the West ⁷. The fact remains however, that – starting in 1946 from a shared base – Jena and Oberkochen developed as two independent companies for more than 40 years.

After German reunification also Zeiss Jena and Zeiss Oberkochen were united again, and have since again been at the undoubtable forefront of lens development. After close to two centuries in the optics industry, the majority of Carl Zeiss’ revenue today (and since some time) comes from sources other than camera optics.

Background to Zeiss’ involvement with the Contax/Yashica system

n.B! all lenses are defined by their history, but this is even more true for the Carl Zeiss Contax/Yashica lenses. Hence, I think it worthwhile to spend a bit more time on the discussing the history of this line of lenses.

The consumer camera/lenses functions of Carl Zeiss (West) were more strictly separate than those of most of its rivals. While many Japanese camera companies wanted it to look like if their camera and lens businesses were separate (Nikon/Nikkor; Minolta/Rokkor; Pentax/Takumar), Carl Zeiss’ camera business (Zeiss Ikon) and lens business (Opton/Zeiss-Opton/Carl Zeiss) really were very independent, and (unlike those Japanese rivals mentioned above) Carl Zeiss had a long history of offering its lenses not only for Zeiss Ikon cameras, but also for various other cameras (most prominently Hasselblad) and applications (especially cinematography).

But while cinematographers and studio photographers are willing to pay considerable sums for a lens, the 35 mm camera and lens business is different, simply because economies of scale ⁸ are on a totally different level. Any company that is able to produce and sell ten times more lenses than a rival is likely to be able to produce a better quality/price -ratio or invest more in marketing or product development. Alternatively, any company that does not sell a lot of lenses cannot remain competitive, profitable and up-to-date.

And herein lay Carl Zeiss’ problem in the late 60s and earliest 70s, because the Zeiss Ikon Cameras were not selling well. The Contaflex was outdated, the Contarex was too expensive, and the Icarex line’s (Icarex 35, Icarex 35S and SL706) chances were marred by infighting, NIH-syndrome and insufficient product development commitments. As a result Carl Zeiss found itself in a situation where production numbers for 35 mm lenses were insufficient to enable Zeiss to remain technologically competitive while also being profitable. In simple terms, Zeiss needed to find volume somehow. Hence, it came that Zeiss shut down its camera manufacturing altogether, and instead entered a co-operation with Yashica of Japan.

History of the Contax/Yashica system

The Contax/Yashica system as well as the eponymous mount were co-designed by Zeiss and Yashica under the aegis of “Top Secret Project 130”. Zeiss’ intended contribution to the co-operation was the name ‘Contax’ as well as lens designs and the manufacturing of some of the lenses whereas Yashica would take care of camera manufacturing as well as some lens manufacturing. Moreover – beside the line of premium ‘Contax’ camera bodies and Carl Zeiss lenses, Yashica could also sell Yashica-branded bodies and lenses. This co-operation gave Yashica a leg up in competing with other Japanese Camera manufacturers while also allowing Zeiss access to the kind of volumes it needed and could not reach by itself.

The Contax (Contax/Yashica) system was unveiled at the Photokina fair in 1974 and the Contax RTS body hit shelves in 1975. While many German pundits thought it an outrage to produce anything named Contax outside of Germany, overall reception was very favourable. Not only would the new system be able to use Zeiss’ optics, also the new body design (especially the ergonomic for which the F. Porsche design studio had been engaged) seemed very promising.

The system was initially centred on aperture priority auto exposure, and the body-lens interface did not allow for the camera body to control aperture. To facilitate shutter priority and program auto, Yashica/Contax in 1984/5 unveiled the 159MM body (MM=multi-mode) and an upgrade to existing lenses so that they would support the full range of auto exposure modes in MM-capable bodies.

While somewhat successful, the the Zeiss-Yashica co-operation was by no means unproblematic. Yashica often felt Zeiss was unwilling to commit to sufficient volume (which likely contributed to production over time increasingly shifting to Japan). Moreover, although Contax/Yashica were at the forefront of the autofocus revolution (as evidenced by the functional prototype unveiled at fotokina 1982) Zeiss killed that development trajectory by claiming AF lenses could not be manufactured to Zeiss’ standards – a move that later led to Yashica’s breakaway AF system (see some details here) as well as the only serially manufactured in-body AF system in the 1996, Contax AX (touched upon here).

While the Contax / Yashica system technically stayed alive until replaced by the less successful Contax N autofocus system, it’s clear that as autofocus took the world by storm in the late 80s, early 90s, the Contax / Yashica system devolved into a niche / aficionado solution in the early 90s.

AEG / AEJ / MMG / MMJ / WTF?

One can hardly browse Zeiss Contax related discussions without encountering four of the three-letter-acronyms in the heading above. They are each constructed from two parts:
• the first two letters (AE/MM) indicate whether the lens is of the earlier (before multi-mode) type (AE) or of the latter (MM)
• the final letter indicates whether the lens has been manufactured in Germany (G) or Japan (J).

AE or MM? Obviously, if you’re intent on using your Zeiss Contax lens on a Contax body offering MM functionality, you will want your lens to support that functionality. Otherwise, there are (again) a lot of self-serving opinions to be found online, that are often based on rather shaky factual grounds:
• MM lenses are newer, hence offer more modern coatings. Probably true – on some level – but as lens manufacturers rarely waited with introducing process improvements, whatever coating improvements were introduced are more likely to have been introduced within the AE / MM series than at the precise moment of change from AE to MM. Therefore, if the newest coatings are your goal, rather aim for later serial numbers than simply going for MM. In general, later coatings (besides more effective) tend to flare towards the violet whereas earlier coatings flare greenish.
• AE lenses were built better. Yes, but not that you would see it on the surface. People with extensive experience servicing Zeiss Contax lenses have noted that some failures (esp. haze and balsam separation) occur more regularly in MM lenses.
• All lenses were redesigned (optically) going from AE to MM. False. Officially only four lenses received a significant redesign going from AE to MM. These are the 25/2.8; 28/2.8; 135/2 and 135/2.8.
• All early lenses are AEG, all later lenses are MMJ. False-ish. Undoubtedly the weight of German-based manufacturing was higher in the AE age than later (and some MM lenses were also manufactured in Germany), but many of the bread-and-butter AE lenses were manufactured in Japan from the onset (e.g. the 28/2.8; 35/2.8; 50/1.7; 135/2.8).
• All AE versions have the ninja star, no MM versions have the ninja star. True, but first: the ninja star is an aperture pattern that is neither circular nor polygonal. Instead it produces a pattern reminiscent of a circular saw blade or ninja star when closed down a bit. The ninja star is never visible wide open, nor is it ever visible once closed down past f/5.6 and the range in which the ninja star appears may be so narrow that it fully falls between two click-stops (as it does on the 50/1.7 and 85/2.8). Also, the severity of the ninja star varies greatly. Most importantly though, opinions differ on whether the ninja star is a bad thing at all. Also, the ninja star is not a trait specific to Zeiss Contax AE lenses, and may in fact show up more strikingly on other lenses.
• Gotta catch’em all? Only one lens has been manufactured in all four (AEG/AEJ/MMG/MMJ) variants, namely the 85/2.8 Sonnar.

G or J? While some hold that lenses manufactured in Germany (by Zeiss themselves) were of higher standard, than those manufactured in Japan (by Yashica/Tomioka), this is likely to be a rather biased opinion. However, it is a fact that (for the first ≈8 years of the co-operation) Yashica/Tomioka were responsible for manufacturing the bread-and-butter lenses (28/2.8; 35/2.8; 50/1.4; 50/1.7; 135/2.8), while the more elaborate lenses were produced in Germany.

Incidentally, it is easy to identify an MM version from an AE version, because all MM versions had the smallest aperture number painted in green. Also the mount of MM lenses have a small prong that the MM bodies use to identify whether the lens is MM-compatible.

Footnotes

1. Focal length is (unless stated otherwise) given in absolute terms, and not in Full-frame equivalent. For an understanding of whether the lens is wide/tele, see ‘Angle-of-view’. ↩︎
2. Picture angle is given in degrees (based on manufacturers’ specs) and concerns the diagonal picture angle. Rule of thumb:
   > 90 ° ==> Ultra-wide-angle
   70–90 ° ==> Wide-angle
   50–70 ° ==> Moderate wide-angle
   40–50 ° ==> ‘Standard’ or ‘normal’ lens
   20–40 ° ==> Short tele lens
   10-20 ° ==> Tele lens
   5-10 ° ==> Long tele lens
   < 5 ° ==> Ultra-tele lens ↩︎
3. Length is given from the mount flange to the front of lens at infinity. ↩︎
4. Diameter excludes protrusions such as rabbit ears or stop-down levers. ↩︎
5. S=straight; R=rounded; C=(almost)circular at all apertures. ↩︎
6. Numbers equal aperture values on aperture ring; • intermediate click; – no intermediate click. ↩︎
7. Online one can find many lengthy and heated disputes stating that only Jena/Oberkochen is the true Carl Zeiss. While many of these discussions are riddled with misconceptions and a poor grasp of facts, they largely also tend to be tainted by ideologies. Those discussions that focus on claims of one or the other Zeiss not really having rights to using designs developed at pre-war Zeiss are especially ludicrous because after the war practically the entire patent catalogue of pre-war German companies was given freely to everyone (the western allied saw this as a form of reparations), hence also kickstarting the Japanese optics industry’s ascendancy (the Japanese optics companies were the most avid users of German optics patents). ↩︎
8. “economies of scale” is a business term signifying the phenomenon where manufacturing costs per unit fall when manufacturing numbers increase. Importantly, while almost all manufacturing industries have economies of scale, some industries have stronger economies of scale than others. Also, for economies of scale to be able to realise their effect, there needs to be a sufficient demand. ↩︎