Zeiss Biogon T* 2/35 ZM
Last updated October 29, 2011
The Powerful All-Rounder
This moderate wide-angle focal length is one of the most popular lenses for rangefinder photography. The Biogon T* 2/35 ZM is the fastest lens in the Biogon family. It offers outstanding performance, distortion-free images and the fast f/2 aperture permits handheld photography under difficult lighting conditions. When stopped down, the lens accurately captures the smallest details, yielding images with very good contrast and ‘sparkle’. Combined with a digital rangefinder camera with a 1.3 crop factor, the lens has an effective focal length of 46 mm, similar to the standard 50 mm lens for film-based cameras. The Biogon T* 2/35 ZM is a favorite of photojournalists and an all around outstanding performer for almost any application.
|Focal length||35 mm|
|M8 equivalent||46 mm|
|Aperture range||2 - 22 (1/3 steps)|
|Focusing range||0.7 m – infinity|
|No. of elements/groups||9/6|
|Angular field, diag./horiz./vert.||63/54/38 °|
|Filter||M 43 x 0.75|
|Dimensions (with caps)||ø 52 mm, length 68 mm|
The following graphs were gleaned from the Zeiss-provided datasheet (PDF) for this lens:
A full review of the Zeiss Biogon T* 2/35 ZM lens, including specifications, performance charts, overview, sharpness and vignetting tests as well as sample images and links for further research.
The Biogon T* 2/35 ZM is indeed a great, all-around kind of lens. A bit wider than a 50mm for more environmental portraits or capturing just a little more of the scene without being considered a true wide angle. Many prefer this focal length over a 50mm for that reason. On a camera such as the M8, with its 1.33x crop factor - makes the 35mm focal length a suitable focal length for approximating a "standard 50mm" as it's effectively a 46mm. The rather fast maximum aperture of f/2 is quite usable in dim situations and allows for a nice separation of your subject from the background. The 35mm focal length allows a larger set of framelines in the viewfinder while still allowing for plenty of room around them, for anticipating action or aiding in framing.
Consider reading about all the things they have in common in our Zeiss ZM Lenses overview.
Like the other ZM lenses, the Biogon is well-built and solid-feeling. The materials and craftsmanship are both of a high-order. The aperture ring has positive, somewhat firm detents from f/2 to f/22 in third-stops. This differs from the Leica standard of half-stops, so it's something to keep in mind if you have a mixed bag. It's useful especially if you shoot slide film but also with the M9 if you're used to dialing in exposure compensation - which is also in third-stops. The focus ring is smooth and well-damped, but not as much as Leica lenses.
The lens is perhaps not quite as sharp wide open as some of the other ZM lenses (for example, the Planar T* 2/50 ZM) but it's still quite sharp. Stopping down even a little brings it right up to par. By f/4 the lens is at its optimum and quite sharp across most of the frame. Stopping down beyond f/4 increases depth of field and further sharpens the borders and corners slightly. At its peak, while sharp - the lens doesn't quite reach the resolution of a lens like the Biogon T* 2,8/25 ZM. Rather, it's a more "gentle" or slightly classic rendering which makes it a great "people lens." That is, It's sharp - but not in your face. One aspect of the lens, somewhat typical of Zeiss lenses in general - is the "3D" look that some images take on. The in- to out-of-focus transition and bokeh of the Zeiss lenses, along with sharp definition of subjects can, under the right circumstances - give a certain pop.
The bokeh is very typical of Zeiss lenses, and differs from more "Japanese style bokeh" in that there's still some definition to out-of-focus objects rather than washing them away. Part of this is due to the fact that this focal length and maximum aperture doesn't afford such a thin depth of field of either longer or faster lenses but also lens design. Therefore, Biogon lenses share a similar look, as do other Zeiss designs.
Contrast on average is high, but slightly subdued as compared to some other ZM lenses. Wide open, the lens has a bit lower contrast which improves at f/2.8 and by f/4 reaches its peak - where it remains stopped down further. Colors are lively and saturated and typically Zeiss - which really pop, especially blues. Distortion is practically non-existent and one of the hallmarks of this lens. There is a fair amount of vignetting from wide open to about f/4 and clears up by f/5.6.
When shot at or near wide open, there can be some chromatic aberrations present in the outer areas under the most extreme contre-jour shooting - but it is very well controlled and stopping down just a little completely eliminates it. Even when shot with the sun directly in the frame, flare is essentially non-existent and instead can produce lovely sunstars (when stopped down). Use of the hood might even be considered optional - though it's never a bad idea to use one and is recommended.
Many point out that for the specifications - a 35mm f/2 lens - that the Biogon is on the large side. The Leica Summicron 35mm f/2 lenses, by comparison - are visibly smaller, especially newer versions. This stems from the Biogon design and general principles at Zeiss. Zeiss prefers to highly correct their lenses, but without giving as much thought to compactness as say, Leica. This is typically done with higher refractive index glass and aspherical elements - the latter of which you won't find in a single ZM lens.
The filter size is 43mm, which differs from the more common 46mm size of many other ZMs. Not a deal-breaker by any means, but something to consider if you're looking to share filters, especially UV/IR filters with other lenses. One great solution is a 43-46mm step ring and standardizing on 46mm filters. This way, you can use the filters on most of the ZMs without consideration and throw on the step ring for use with the Biogon T* 2/35 or Planar T* 2/50 ZMs as needed. It's worth noting that the Leica 43mm UV/IR filter is of a different thread pitch and will not work properly - though it can be screwed in to the point of binding a tiny bit and it'll hold just fine (do not exceed this point however).
Coding for Digital Ms
This lens is typically given the 6-bit code of the Leica Summicron-M 35mm f/2 "pre-ASPH" (11310/11311) - which works well on both the M8 and M9 bodies. The code for this is 000110 and can be either marked with a template and a Sharpie marker or machined into the flange and properly painted for a more permanent solution via a third-party. The 35mm focal length is about at the limit and so doesn't necessarily need to be coded for in-camera corrections (though useful for the EXIF info and to differentiate between lenses). You might want to consider it however, especially when used with a UV/IR filter as it can introduce slightly cyan corners. There is also some vignetting - and the firmware can correct all of this nicely.
The Biogon T* 2/35 ZM would be a great option as your primary or secondary lens and can be used under all circumstances. A sharp lens with great color and signature with a performance that's very good in general and quite lifelike. Very much lives up to the definition of the Biogon design. With an attractive price and all the usual "Zeissisms" it's a great value and should be on your short list.
Vignetting was tested using the M9 at ISO 160, firmware version 1.162:
|Lens detection set to OFF|
|Lens coded as a Summicron 35mm f/2,0 "pre-ASPH" (11310/11311) and lens detection set to AUTO|
This test is preliminary, and only tests the center performance - but it should give you an idea of what to expect. It was conducted by shooting a test target at MFD (.7m) which represents a worst case scenario as non-macro lenses are generally optimized for infinity. Images were shot at the various apertures with an M9, mounted on a tripod. No alterations were done to the image except for auto level and they are 100% crops:
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