Zeiss Planar T* 85mm f/1.4 (Contax N to Canon EF) - Review / Test Report
Lens Reviews - Canon EOS (APS-C)

Review by Klaus Schroiff, published December 2007

Lens kindly provided for testing purposes by Markus Stamm!


Some of you out there may still remember the old Contax systems. Back in 2000 Kyocera started a bold last attempt to rival the inevitable by releasing a brand new AF SLR system - Contax N. The system found some friends but Kyocera abandoned the market thanks to a disastrous execution and time-to-market of the Contax N Digital - a 6mp full format DSLR. You may think that this was the end of the story but that's not totally true. Naturally Contax N lenses (designed by Zeiss) don't fit to other system cameras but technically they are very related to Canon EF lenses - they use an electronically controlled aperture mechanism as well as a build-in AF motor (using either a conventional micro- or ultrasonic-motor). Obviously the lens control logic is so similar that a smart fellow (Conurus) reverse-engineered the data flows and created a "smart" Contax N to Canon EF adapter. This adapter is not a plug'n play thing but actually a mount conversion. It's not a cheap procedure either (350-750US$ depending on the specific Zeiss lens) but it can revive these babies to behave like a native Canon EF lens - including a camera controlled AF and aperture plus (mostly) valid EXIF data.

One of the supported lenses is the Carl-Zeiss Planar N T* 85mm f/1.4 - a classic Zeiss lens although it is NOT identical to its recently released Zeiss ZF or Sony/Zeiss AF cousins. The original symmetrical Planar design was invented in 1896(!) but naturally it has been optimized over the decades and it is one of the most successful and most copied in the business. "Planar" originates in the German word plan ("plane" in English) and refers to the flat reproduction characteristic (minimal field curvature).

As usual we'll have a look how the T* 85mm f/1.4 on an APS-C DSLR. I'm aware that some of you may have wished a test on a full format DSLR but these tests will start based on the successor of the EOS 5D.

The 85mm f/1.4 is a beautifully crafted monster of a lens. You may notice that the EOS 350D looks dwarfish in comparison. The lens requires huge 82mm filters so be prepared to cry when investing into a polarizer. Thanks to an internal focusing (IF) mechanism the physical length remains constant regardless of the focus distances. The very broad rubberized focus ring operates smooth and accurate.

The T* 85mm f/1.4 features an ultrasonic AF motor. It's not a speed daemon but reasonably fast and relatively accurate (the EOS 350D tends to have troubles with ultra-large aperture lenses in general). Besides the mount conversion Conurus faced one little obstacle - Contax N lenses have no AF/MF switch (selected on the camera). However, he found a workaround for this: you have to set the (otherwise useless) aperture ring to the smallest aperture for manual focusing. This may be an unusual thought but it works just fine. Interestingly the new firmware (v2.+) has a new "AF micro-adjustment" feature - similar to the new EOS 1D III it is possibly to do a focus fine-tuning so if you're experiencing a front/backfocus problem you can easily correct this yourself.

Equiv. focal length136 mm (full format equivalent)
Equiv. aperturef/2.2 (full format equivalent, in terms of depth-of-field)
Optical construction10 elements in 9 groups
Number of aperture blades9
min. focus distance0.83 m (max. magnification ratio 1:8.9)
Dimensions90 x 80 mm
Weight800 g
Filter size82 mm (non-rotating)
Hoodmetal, barrel shaped (snap-on)
Other features-

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