Voigtlander APO-Lanthar 90mm f/3.5 (on Sony NEX) - Review / Test Report
Lens Reviews -
Sony Alpha/NEX (APS-C)
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Review by Klaus Schroiff, published September 2010
The Voigtländer APO-Lanthar 90mm f/3.5 in another affordable tele prime with Leica M39 mount. The lens name may sound familiar to DSLR users - Cosina (the actual manufacturer) offers another APO-Lanthar 90mm f/3.5 SL II for Canon EOS/Nikon F/Pentax K but the optical and mechanical design is different. An interesting aspect of the lens is the APO design - as claimed by Cosina at least - which is a fairly rare feature in medium tele prime lenses. In theory an APO design provides a superior correction of color-related aberrations (Lateral and longitudinal CAs) but in practice very few lenses qualify here. We'll see. The Leica M39 version of the lens can be used on a Sony NEX via a Leica M39 to Sony NEX adapter.
Such adapted lenses can only be used with manual focusing and "working aperture" - there's no data coupling whatsoever here. The field-of-view is equivalent to about 135mm in and in terms of depth-of-field it behaves like a f/5 lens in this scope - while not overly fast it's still a rather obvious solution for portrait photography for instance. If you look around you should be able to find this lens for about 400-450EUR/US$ and it's often available for much less over at eBay.
It's a full-metal construction built to very high standards. The focus ring operates very smooth (dampened). The lens extends somewhat when focusing towards shorter distances. Typical for adapted lenses, a change of the aperture setting is applied immediately so you can check the effect on the depth-of-field on your screen (without the darkening like when stopping down a DSLR with a conventional optical viewfinder). The lens is supplied with a screw-in metal lens hood.
Manual focusing may sound like a major annoyance but it is not that bad actually. On Sony NEX cameras you can easily switch to a magnified focus view so accurate manual focusing is really simple unless you try to track a moving object of course. Such a 90mm lens is probably also the meaningful (hand held) limit for manual focusing in magnified LiveView - the screen image tends to be quite shaky when adjusting the focus.
|Equiv. focal length||135 mm (full format equivalent)|
|Equiv. aperture||f/5.3 (full format equivalent, in terms of depth-of-field)|
|Optical construction||6 elements in 5 groups, 1x ED element|
|Number of aperture blades||10|
|min. focus distance||1 m (max. magnification ratio 1:?)|
|Dimensions||90 x 51 mm (inc. hood)|
|Filter size||39 mm (non-rotating)|
|Hood||supplied, screw-in, barrel-shaped|