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Introduction

Carl Zeiss designed and Sony manufactured Sonnar T* 135mm f/1.8 ZA was one of the first Carl Zeiss lenses exclusively licensed for the (then new) Sony Alpha system. The lens was introduced under much fanfare in late 2006 and instantly became a major differentiating point against established players like Canon and Nikon. The lens currently retails for ~US$1,500 new, but can be found for ~US$1,000 on used markets.

The optical construction of the lens consists of 11 elements in 9 groups, including 2 ED glass elements, which are supposed to reduce the amount of chromatic aberration. The build quality of the lens is superb and resembles build of other Carl Zeiss designed Sony lenses. The barrel is all metal, as are the focusing ring and the bayonet type lens hood. The lens weighs 995g (2.1lb) and measures 89 x 115mm (3.5 x 4.52in). The lens employs internal focusing mechanism so that the length of the lens remains constant at all times. The focusing ring is decoupled and does not move during focusing, allowing for both auto-focus as well as manual operation. The lens focuses down to  72cm (28.3in), providing 0.25x magnification. The aperture is fully electronic and is controlled from the camera, with the minimum supported aperture of f/22. The lens accepts 77mm screw-in type filters.

 

cz-135mm-f18za

 

Sonnar 135mm f/1.8 ZA is a full frame lens but is fully compatible with all Alpha mount cameras, including all APS-C bodies as well as Sony NEX cameras (when used with an adapter). The EFOV of Sonnar when used on APS-C cameras will be 203mm. The manufacturer's box includes the lens, front/rear caps, metal lens hood, soft leather pouch and registration card. Within the scope of this review, the lens was evaluated on a full frame Sony a850 camera.

 

Summary
Lens Composition 11 elements in 9 groups
Angular Field 18 degrees
Minimum Focus 72cm/2.3ft
Focusing Action AF/MF
f-stop Scale f/1.8-f/22, electronic
Filter Size 77mm
Lens Hood Metal (included)
Weight 995g/2.1lb
Dimensions 89x115mm/3.5x4.52"
Lens Case Soft leather pouch

 

 

Handling

Sony Carl Zeiss Sonnar 135mm f/1.8 ZA is one of the most interesting lenses I have had a chance to evaluate recently. For starters, Sonnar is the current speed king among 135mm lenses. Both Canon, as well as Nikon offers 135mm f/2 versions in their lineup, but no-one else goes for the f/1.8 aperture. In the days past, particularly when 135mm focal range was more fashionable among users, a couple of other 135mm f/1.8 lenses were available on the market, most notably Pentax smc P-A 135mm f/1.8 in Pentax K mount and Sigma 135mm f/1.8 in T mount (sold under Soligor brand name in the US, and believe it or not also available in MA mount, albeit in very limited quantities). But the absolute speed record in this class actually belongs to Vivitar, which was offering 135mm f/1.5 lens in T mount. But all these lenses are history. The two more appropriate reference points for the ZA Sonnar should probably be the Conatax versions of 135mm lens manufactured by Kyocera up until 2005. The Contax Sonnar 135mm f/2.8 was a fairly inexpensive but a very decent performer, that costs only a fraction of the Sonnar ZA. Contax Planar 135mm f/2 on the other hand cost about what the modern Sonnar ZA costs and was not a particularly popular lens in its days. But, I don't really plan to compare these two lenses, firstly because the ZA lens is clearly a heavily redesigned lens, with more elements/groups, and secondly because adapting a Contax lens to Sony is a pain in the neck - you need to replace the entire mount, which would set you back ~US$100. On top of that, I no longer own Contax  lenses and it's doubtful anyone lending me theirs would be too keen on having their lens tinkered with.

ISO 400, 1/320, f/1.8, 135mm

Ok, enough with the history. Sonnar is one of the bulkiest 135mm lenses I have seen. The bulk (and weight) come from the fast aperture and the optical design, which employs large front elements. The overall weight of the camera/lens combo is rather on the heavy side - while it is still possible to hold the camera/lens in one hand, the front-heavy Sonnar puts quite a bit of pressure on the wrist, so you are likely to find yourself using your second hand to support the lens at the base. The lens does draw attention in public though - expect puzzled and curious looks from passersby when you point that huge front element in their direction. The combo balances decently on a tripod, although I'd recommend using a good ballhead with tight pressure control to prevent the downward drip. On smaller cameras, particularly Sony NEX, the lens looks ridiculous - you basically don't even see the camera behind such a bulky lens. Add a lens hood to that, and well, you get the point...

The lens includes a DOF scale, with markings at f/22 only, making the DOF scale almost useless to anyone planning to use the lens in a preset mode. Considering that the markings are positions fairly close to each other, it is impossible to accurately tell where your focusing range is going to be, probably somewhere in the 10m to the infinity range, but that's the best estimate one can make here. Ultimately, the lens is designed with auto-focusing operation in mind and given that the focusing ring rotates for about 110 degrees going from the closeup to the infinity, the DOF scale is probably an intentional oversight here. And unlike the Distagon 24/2 ZA, reviewed recently, Sonnar does not have an AF/MF switch on the lens barrel, so you would need to switch the camera itself into the manual mode if you decide to focus the lens manually. There is, however, a focus lock button which can also be re-programmed by the camera to activate the DOF preview.

Speaking of the auto-focusing. The AF on the lens is achieved with mechanically driven pin, which locks into the screw slot on the camera mount. This results in a somewhat noisy operation, reminiscent of Nikon pin-driven AF operation, which is also achieved with a mechanically driven pin. The focusing speed is decent, but cannot be compared to the speeds of SSM enabled lenses. Same goes for the focusing accuracy, which particularly suffers at closeup distances, where the lens tends to hund fairly extensively, often locking on everything except what you want it to lock on.