The Contax G90, officially known as the Carl Zeiss Sonnar T* 90mm f/2.8, was designed for the autofocus Contax G1 and G2 camera bodies. The Contax bodies are considered advanced film cameras and serious photographers still use them today. The Contax name is famous for its technological innovations and its close relation with the Zeiss family of lenses.
The Zeiss lenses for Contax rangefinder mount most notably include the 28mm Biogon, 45mm Planar, and 90mm Sonnar. The 35mm Planar was released at a later time and seemed not as popular in those days.
When coupled with a Contax rangefinder camera, the 90mm Sonnar had problems with autofocus (although this issue was controversial). However, the quality of the lens (together with the 28mm and 45mm) was beyond any doubt among the best in its class.
I have such pleasure in using this lens, partly due to the Zeiss brand – I can never imagine myself procuring a Zeiss lens at such an attractive price. The Zeiss for Contax G lenses cost merely a fraction of the cost of the ZM (for Leica), ZE/ZF (for SLF) mount Zeiss glass. But you can of course argue that the Contax lenses are of older design, have more glare, etc.Today, the Japanese (and the Chinese who copies them) successfully engineered Contax-to-NEX mounts so that these lenses can now be adapted to a digital body. Other than the wide angle G16 and G21, other Zeiss for Contax G lenses do not have much problem adapting to the NEX. Of course, these lenses when mounted to the NEX loses autofocus ability.
You can refer to the specification sheet according to Zeiss. It weighs 240g (it is featherweight compared to DSLR telephoto primes!) and has a simple lens design of 5 elements in 4 groups. Its focal length of 90mm is equivalent to 135mm on the NEX’s cropped sensor (x1.5) which makes it ideal for outdoor portraiture and general telephotography. Its minimum focusing distance is 0.91m and I don’t find it a problem in day-to-day use.
Sharpness and pitfalls
The lens offers classic Zeiss quality, with vibrant colors and sharpness even wide open. It is considered to be in the same league as a Leica in terms of sharpness. Colors are rendered beautifully, especially the reds and yellows and skin tones look natural. It is an ideal outdoor portraiture lens; unless you find it too sharp to use!
Chromatic aberration seems to be a problem when used wide open. Once it is stopped down it is a stellar performer.
When used in indoor conditions or in poor light, you may have to bump up the camera’s ISO setting. Without modern stabilization technology, a 135mm equivalent may be too much for your hands to handle (i.e. susceptible to shaking).
Here are some of my favorite pictures:
1. Petals and glass house
Color and contrast
The color is vibrant, and the lens is sharp even wide open. On the NEX’s cropped sensor (x1.5) the focal length becomes 135mm which makes it ideal for outdoor portraiture and general telephotography. The quality of the bokeh is average to good, but not superb. After all, it’s not your 85/1.2L. The f2.8 aperture may not produce creamy bokeh, but as a telephoto it offers good subject isolation.
If you have a more advanced focusing ring adaptor (i.e. Metabones or similar), you will have an easier time focusing with this lens on the NEX. After you get accustomed to it, you will enjoy the colors and contrast of a Zeiss legend.
4. Red Leaves