Carl Zeiss Sonnar T* 135mm f/2.8 Carl Zeiss Sonnar T* 135mm f/2.8

Introduction

Carl Zeiss Sonnar T* 135mm f/2.8 is one of four Sonnar telephoto lenses that Zeiss used to manufacture in the C/Y mount (the other three lenses being 85mm, 100mm and 180mm). The company discontinued manufacturing Sonnar 135mm f/2.8 in C/Y mount after Kyocera, which holds joint development rights for the Contax brand name, exited camera business in 2005. Regretfully, Carl Zeiss, which created the original Contax camera system, cannot  re-use the brand name for another couple of years (until the contract with Kyocera expires). However, it's widely speculated that Zeiss will be interested in resurrecting the Contax lineup of cameras and lenses sometime in the future. In the meantime, Zeiss re-introduced Sonnar T* 135mm f/1.8 in ZA format for Sony's range of digital SLR cameras. The C/Y mount Sonnar is one of the most affordable lenses in the Carl Zeiss lineup - good quality used copies can be found for about US$200-$250 on eBay, while a new copy of Carl Zeiss Sonnar in ZA format for Sony SLR costs about US$1,350 at various online retailers.

The optical construction of the lens consists of 5 elements in 4 groups. The build quality of the lens is pretty solid - the lens mount and both barrel cams are metal. So is the built-in slide-type metal lens hood that could be extended from the front of the barrel to reduce amount of stray light hitting the front glass element. Both aperture and focus rings are fully rubberized. The inner lens cam extends by a few centimeters when focusing towards closelup. Both inner lens cam and the built-in lens hood wobble a little bit inside the lens, slightly diminishing the overall feel of the lens.

The minimum focusing distance of the lens is 1.6m (5.5ft) and the minimum aperture is f/22. In the domain of telephoto lenses, Carl Zeiss Sonnar T* 135mm f/2.8 is average in size and weight - 585g (1.3lb) and 7.8 x 13.1cm (3.1 x 5.2in). It accepts 55mm screw-in type filters.

 

Image

To test the lens on Canon EOS body, I used a generic Contax/Yashica to EOS adapter without AF confirmation. Sonnar T* 135mm f/2.8 has very little surface area that does not move or rotate (the focusing ring is pretty much the entire lens barrel!), so detaching a tightly screwed-in adapter proved to be somewhat tedious - be careful not to break aperture ring or lens hood in the process.

 

Summary
Lens Composition 5 elements in 4 groups
Angular Field 18 degrees
Minimum Focus 1.6m/5.5ft
Focusing Action MF
stop Scale f/2.8-f/22, manual
Filter Size 55mm
Lens Hood Built-in + No.5 screw-in (optional)
Weight 585g/1.3lbs
Dimensions 78x131mm/3.1x5.2"
Lens Case No.3 (included)

 


Field Tests

It seems like 135mm focal length is going through a decline in popularity among photographers. At least if we judge the popularity of a particular lens by the number of lenses currently being manufactured for various camera systems. Then the 60s, 70s and even 80s were easily the golden age of 135mm, with pretty much every camera and lens manufacturer offering at least one, and in many cases two or even three variants of a 135mm prime. Carl Zeiss Jena had Sonnar 135mm f/3.5 and f /4, Pentacon had 135mm f/2.8 and 135mm f/4, Schneider had 135mm f/3.5, Olympus had 135mm f/2.8 and f/3.5, Pentax had 135mm f/2.8, the list goes on... Even Carl Zeiss itself used to offer three versions of 135mm lenses - Planar T* 135mm f/2, Sonnar T* 135mm  f/2.8 and Tele-Tessar 135mm f/4. The Tele-Tessar was discontinued during Rollei SL35 era, but the other two carried on into Contax/Yashica mount. These days however, only Canon, Nikon and Sony offer 135mm lenses in their lineups, with the latter one actually offering a Zeiss Sonnar design, as mentioned earlier. It seems that the focal length is being squeezed out by more popular 100mm or even 85mm on the shorter end, and by 200mm on the longer end. There is, after all, very little reason to own both 100mm and 135mm since the focal length difference is not that significant for all practical purposes.

These days, Contax Sonnar 135mm f/2.8 has become a started alternative lens for many gear-heads. As any alternative lens, the 135mm Sonnar does require special handling and hence is not really suitable for the masses. Firstly, this is obviously a manual focus lens, and since most modern cameras (particularly APS-C type) have rather small and dark viewfinders, with no focusing aids, the focusing action can be rather tedious. You can rely on your vision, or use live view if your camera has one, but I would recommend getting an AF confirmation adapter - it will help you improve the accuracy and speed up focusing. The focusing action itself is  reasonably accurate - the focusing ring rotates for about 180 degrees from the infinity to the closeup, with higher precision in the shorter focusing range. Secondly, even if you end up getting an AF chipped adapter, you will still have to manually stop down the aperture since there is no coupling between the lens and the camera. The stop down metering process does take some time getting used to and it obviously slows down your shooting since you need to first focus the lens, then stop it down to desired aperture setting, meter and only then shoot. You might seriously consider getting a dedicated spot meter, particularly since majority of cameras overexpose shots with fully manual aperture lenses stopped down to smaller apertures.

On its old Contax web site, Carl Zeiss states that the 135mm Sonnar is "Outstanding for landscape photography, flora and fauna studies, portraits and others where a telephoto effect is desired without the undesirable flattening of perspective prevalent with longer focal lengths'. 'Huh?' you might say and your reaction is correct - basically what Zeiss was saying about this lens is that you can use it for pretty much any purpose, but because this is a wider end of telephoto focal range, the view perspective does not get flattened that much as with say a 300mm lens. Well, that does not really increase our understanding of this particular lens since any 135mm prime would deliver less perspective flattening then a 200mm, a 300mm or a 500mm. What I would have preferred Zeiss say is that the lens delivers excellent image resolution with corner to corner sharp results. The lens was indeed pretty sharp in the field and behaved quite well on both APS-C as well as FF Canon cameras. Center image resolution was universally outstanding, whether you shoot at f/2.8 or f/11. Borders were reasonably sharp with wide open aperture and outstanding from f/4 all the way through. Also, there did not seem to be any noticable difference in how the lens performed at closeup vs infinity focusing. Notice me saying 'reasonably'. This is because while you can notice a little bit of softness around borders at wider apertures, for practical reasons this should not ruin your pictures, even if you leave them as is with no sharpenning applied during post-processing.

Speaking of the perspective flattening. If you are planning to use the lens for portrait type of work, which is the most common use for 135mm lenses like Sonnar, the flattened perspective in combination with shallow DOF would typically improve the 'feel' of bokeh - the out of focus area, blurring it better and making the subject in focus stand out . If the lens is also capable  of delivering high contrast levels in the focused areas, you would get the feeling of the subject 'popping' out of the picture. The so called '3D feel' of the lens sought by so many alternative lens users chasing after Zeiss and Leica lenses. Now, Sonnar T* 135mm f/2.8 does not deliver a particularly thin DOF like one might see in faster lenses - the shot below simulates the DOF at f/2.8 and close to the minimum focusing distance. However, since the lens does flatten the perspective, you can, depending on the situation, achieve a decent looking bokeh, as can be seen in the photos of flowers in the sample image gallery. Notice however, that the bokeh 'looks' different in the three flower shots. This is because the different focusing distance to the flower. Guess which of these was done at the minimum, close to minimum and  not-so-close to minimum focusing distance?

 

ISO 400, 1/160, f/2.8, 135mm (Canon 5D)

Continuing on the subject of bokeh. The shot below demonstrates a relatively simple scenario when the lens is used at the close to minimum focusing distance and wide open aperture. You can notice that the out of focus highlights have rather pronounced, bright edges, with few of them having a light greenish tint. This is likely because the lens was over corrected for spherical aberration, which is not that uncommon in optical designs optimized for end-to-end frame sharpness. The effect is not very pronounced, so it should not ruin your pictures. Finally, on another positive note, you can see in all samples that there is no visible sign of double edging around out of focus areas, which can become quite distracting and ruin the tranquility of even the best bokeh.

ISO 400, 1/100, f/2.8, 135mm
ISO 400, 1/100, f/2.8, 135mm (Canon 5D)

 

Flare handling, which typically is more of a problem in wide angle lenses, could be considered normal with Carl Zeiss Sonnar T* 135mm f/2.8. In extreme conditions, the lens does show flare pretty much throughout the aperture range, but a rare lens would do much better here. Shots above demonstrate what happens if you point the lens towards the sun and don't use the built-in hood. In this case, the sun was positioned right above the picture frame, with sun rays peaking through the tree branches and hitting the lens at ~55 degrees. As one would expect, you get reduced contrast and blown out highlights as well as light streaks and spots, particularly at wider angles. Hopefully you are not going to compose your pictures this way, but if you do, use a built-in lens hood at least.

 

ISO 100, 1/500, f/2.8, 135mm
ISO 100, 1/60, f/8, 135mm

 

Vignetting on a full-frame camera was well under control - at f/2.8 vignetting was pretty minimal and basically non-existent once stopped down to f/4. Vignetting on an APS-C camera was non-existent throughout the aperture range. For a telephoto lens this does not come as a big surprise.

 

Vignetting @ f/2.8 - full frame vs 1.6x crop
Vignetting @ f/2.8 - full frame vs 1.6x crop

 

As mentioned earlier, one of the most often quoted by alternative users reasons for going after Contax lenses is their superb color reproduction. That is where a good lens can really show its colors, pardon the pun. A combination of high contrast in focused areas, high resolution and accurate color reproduction is what can give your photos what is often described as that true 'Zeiss' or 'Leica' look and feel. And while many lenses out there showcase solid resolution capabilities, not that many handle color reproduction well, with Sonnar T* 135mm f/2.8 lying somewhere in the middle. Color reproduction generally speaking was quite decent, and images did carry enough contrast in shadows and midtones to make your pictures look lively, but I did not notice anything particularly outstanding with this lens. It just seemed that Sonnar is capable of handling most situations well enough for the majority of users, but there was nothing that would make it stand out here from many other quality lenses out there. Still. for a 20+ year old design and sub US$300 lens, the results are quite good overall.


ISO 100, 1/1600, f/2.8, 135mm (100% crop)
ISO 100, 1/1600, f/2.8, 135mm (100% crop)

 

 


Lab Tests
Please note that MTF50 results for APS-C and Full-Frame cameras are not cross-comparable despite the same normalized [0:1] range used to report results for both types of cameras.


Canon APS-C: Carl Zeiss Sonnar T* 135mm f/2.8 showed very solid but not unique for a medium telephoto lens results in the lab. Performance in the center was outstanding throughout all tested aperture settings. Border performance lagged center a little bit but remained even throughout the aperture range. At its peak from f/2.8 through f/8 the lens would be capable of producing outstanding 16in and decent 19in prints. Conclusion?  The lens performance is right within the range expected from a solid, but not necessarily exceptional, lens and that is all that there's to say about it.

 

MTF50 (Line Width/Inch on the Print) @ 135mm
MTF50 (Line Width/Inch on the Print) @ 135mm

 

Normalized raw MTF50 @ 135mm
Normalized raw MTF50 @ 135mm

 

Like with majority of other Zeiss lenses, chromatic aberration (fringes of color caused by sharp contrast transitions) was pretty much non-existent throughout the tested aperture settings.

 

Image borders @ 135mm (100% crop): f/2.8 vs f/8
Image borders @ 135mm (100% crop): f/2.8 vs f/8

 

Canon FF: The lens continued to perform quite well even on a full-frame camera. Center performance is pretty solid straight from f/2.8 and while performance degrades a bit towards f/11, it never falls apart. Same applies to the border quality, which remains pretty consistent throughout the tested aperture range. Conclusion? While the lens does not produce the best MTF results in its class, very even performance across the frame and throughout tested aperture range should still warrant a closer look at this medium telephoto lens.

 

Normalized raw MTF50 @ 135mm
Normalized raw MTF50 @ 135mm

 

The lens showed minimal amount of barrel distortion - at ~0.22%, distortion should not even register in regular photography.

Distortion (FF) @ 135mm

Distortion (FF) @ 135mm

 

CA was pretty minimal, almost negligible both in the center (~0.4px across tested aperture levels) as well around borders (~0.6px across tested aperture range).

 

Image borders @ 135mm (100% crop): f/2.8 vs f/8
Image borders @ 135mm (100% crop): f/2.8 vs f/8

 


Alternatives

Carl Zeiss lineup of lenses in the C/Y mount includes a couple of interesting alternatives to Sonnar T* 135mm f/2.8. A faster version of the 135mm prime, Planar T* 135mm f/2 can occasionally be found these days, and while this lens showcases outstanding performance, it's price-tag is simply astronimical when compared to the commonly available Sonnar. You might want to consider Carl Zeiss Planar T* 100mm f/2, which is not as rare as Planar T* 135mm f/2, or its close cousin Makro Planar T* 100mm f/2.8. Both lenses offer superb image quality at a somewhat higher price tag. The recently released Carl Zeiss Makro Planar 100mm f/2 ZF is another potential choice. From outside of the Carl Zeiss lineup of lenses, take a look at Leica's discontinued Elmarit-R 135mm f/2.8. Of course there are quite a few other options, but if you are a Canon user, you might not even have to go the extra mile in your search for the best 135mm - Canon EF  135mm f/2L USM is an outstanding prime that does not require you to worry about all that manual this and manual that nonsense.


Recommendation

Carl Zeiss Sonnar T* 135mm f/2.8 is a pretty interesting choice when it comes down to medium telephoto lenses in the C/Y mount. As I have been saying in other reviews, there is no need for a lens to produce MTF results that go off the chart to be considered an outstanding choice. Sonnar T* 135mm f/2.8 falls within this description: performance on both APS-C and FF cameras are pretty solid. Combination of good build quality, reasonable handling of various artifacts like vignetting and distortion, as well as affordable price, should make this lens a good choice for anyone considering it as an alternative to their mainstream primes. All that of course assuming you're willing to deal with a manual lens.