Sony branded Carl Zeiss Sonnar T* 24mm f/1.8 ZA is the first of the Zeiss designed and Sony manufactured lenses that was released for the new NEX mount. Sony markets Sonnar as a premium, professional grade lens, with a matching $999.99 price tag. This makes Sonnar the most expensive E mount lens, although Carl Zeiss Distagon T* 24mm f/2 ZA, which has been available in Sony alpha mount for close to two years is slightly more expensive, going for ~$1,300.
The optical construction of the lens consists of 8 elements in 7 groups, with 2 aspherical surfaces and 1 ED). The build quality of the lens is good, but not of the same quality as the traditional SLR and rangefinder lenses manufactured by Zeiss. The quality of the lightweight metal barrel of the lens seems to be on par with the quality of other Sony branded Zeiss lenses like Zeiss Vario-Sonnar 24-70/2.8 ZA, which means it should, at least in theory, withstand a fair amount of abuse. But unlike its SLR brethren, Sonanr 24/1.8 is smaller and lighter, measuring 63x65.5mm (2.4x2.5in) and weighing 225g (7.9oz). The minimum focusing distance is 16cm (6.2in). The aperture is electronic and is controlled from the camera. Min aperture level is f/22. Like all other E mount lenses so far, Sonnar 24/1.8 accepts screw-in type filters - filter diameter is 49mm.
The manfuacturer's box includes the lens, front/rear caps, plastic petal-shaped lens hood, lens pouch and warranty/registrations cards. The lens is compatible with E mount cameras and within the scope of this review was tested on 16Mp and 24Mp APS-C type Sony NEX-5n and Sony NEX-7 cameras. On APS-C type cameras, the EFOV of the lens is 36mm.
|Lens Composition||8 elements in 7 groups|
|Angular Field||84 degrees|
|f-stop Scale||f/1.8-f/22, electronic|
|Lens Hood||Plastic ALC-SH114 (included)|
|Lens Case||Soft pouch (included)
|Retail Price||$999 (2012)|
Carl Zeiss Sonnar 24/1.8 ZA for NEX system is a first Sonnar lens in its focal length category. You heard that right - no no Sonnars with FL shorter than 40mm were ever produced. Wait, you may say at this point, what about all the Vario-Sonnars like 16-35/2.8 ZA and 24-70/2.8 ZA or Contax 35-70/3.5? Ok, so we need to distinguish between the Sonnar design and Sonnar brand name. Zeiss owns the brand name and can slap it on any lens it wants. Vario-Sonnar is a branding. Sonnar design, on the other hand, traces its roots to the classical triplet, or actually its derivative, the Ernostar. Bertele, who designed Sonnar, connecting Ernostar's third and fourth elements into a single group, which reduced reflection and improved contrast of the lens. Later on, Bertele replaced the last element with a cemented duplet, which increased the max aperture by almost a full f-stop to f/1.5. Over the next few years, Sonnar design saw minor variations, but often meant a high speed lens with a small number of optical groups (typically two to four) and at least one cemented triplet group. Drop the word 'small number' and you get Vario-Sonnar. And guess what... Sonnar 24/1.8 does not actually have a triplet group and has a total of 7 groups. Compare that to the rangefinder Sonnar 50/1.5 ZM, which has 4 groups and 6 elements and includes a triplet group or to the old, pre-war Contax 50/1.5, which has 7 elements in 3 groups, also with one triplet group.
The true Sonnar designs (if there's really such a thing, of course, as a 'true' Sonnar) existed in 40mm to 250mm focal length for years, with shorter FLs available only for rangefinders due to their protruding rear elements. The 40mm Sonnar was manufactured only by Rollei in LTM mount (and prior to that as a build-in lens in Rollei 35S), while 50mm Sonnars were manufactured pretty much by everyone, including Canon, Nikon and KMZ. The shortest SLR Sonnar available up until now is the Contax 85/2.8. So you see, technically speaking Sony's Sonnar 24/1.8 is breaking a new ground here, possible only because of the mirrorless camera design and NEX's short flange distance, except that the lens does not strictly follow Sonnar design.
Ok, enough with history. While its larger ZA cousing sport all standard lens features, Sonnar 24/1.8 is a true E mount lens and thus skimps in a number of areas many consider normal in the SLR world. No aperture ring (ok, this is becoming normal actually with most new lenses sporting electronic aperture). No DOF scale and no distance scale - the lack of both being a pain in the neck if you're trying to preset your lens in manual mode, or when you want to check yor focusing distance. Sonnar 24/1.8 does not have OSS either, which is a bummer. I would buy an argument that a $199 16/2.8 lens does not need one, but clearly a premium level lens like Sonnar should have had one, particularly considering that its EFOV is really ~35mm.
The lens is fairly compact and light and feels 'at home' on NEX cameras. It has a slightly larger profile than the kit 18-55/3.5-5..6 lens, which by itself is very compact. Like with other NEX lenses, Sonnar 24/1.8 supports both AF and manual focusing along with manual focus override. The focusing ring does not have a limiter and rotates endlessly in either direction. There's about 90 degrees of rotational thrust when going from the MFD to the infinity, which is about average for lenses of this focal length. AF is fairly fast and silent, typically taking less than a second to lock on target. There's a little bit of hunting at MFD and in low-lit conditions, which is also typical for contrast detection based AF systems. Continuous AF in movie mode is also supported and the camera refocuses the lens with very little delay.