Sigma AF 135-400mm f/4.5-5.6 APO Aspherical RF - Review / Test Report
Lens Reviews - Canon EOS (APS-C)

Review by Klaus Schroiff, published May 2006

Special thanks to Christian Mikolaschek for providing both the EOS 350D and the lens!


The Sigma AF 135-400mm f/4.5-5.6 APO Aspherical RF is one of the few budget lenses that go beyond the 300mm barrier. At a price around 500EUR/US$ it is certainly a very interesting option for sports or wildlife photographers who cannot or don't want to spend a fortune for a long tele lens. The tested sample is an older variant without Sigma's new DG coating. However, regarding the unaltered optical design the findings should be also valid for the successor. The Sigma is a full frame lens but as usual we'll have a look how it performs on an APS-C DSLR where its field-of-view is equivalent to a whopping 216-640mm.

The optical design of the lens is made of 13 elements in 11 groups including three SLD (Special Low Dispersion) elements and one aspherical element (quite unusual for a tele photo lens). Due to the 400mm setting the Sigma cannot be a small lens - the required amount of glass comes with a penalty in size and weight (89x181mm, 1210g). As you can observe in the product shot above the lens extends significantly when zooming towards the long end of the range. The included barrel-shaped hood adds quite a bit of extra length on top. Sigma was smart enough to implement a detachable tripod collar - otherwise the camera-lens combo would have been way too unbalanced on a tripod. The aperture mechanism has 9 blades. The min. focus distance is 2-2.20m resulting in a max. magnification of 1:5.3 at 400mm. The filter size is 77mm.

Despite its quite impressive sight it is NOT a designated EX (Excellence) lens and it shows here and there. The first contact is pretty positive - the lens feels massive and very well build with pretty tight mechanical tolerances. Unfortunately the early impression fades when using the zoom ring. Despite the two-touch design it is really tough to zoom to a precise position due to a very stiff, high-friction control ring. The focus ring is reasonably smooth but very small and not damped. Even worse the positioning of the ring just in front of the tripod collar ring makes it cumbersome to use and during AF it remains coupled to the AF motor (thus it rotates during AF). The conventional AF drive is quite fast thanks to a RF (Rear-Focusing) design. The generated AF noise level is moderate. In the tested sample the AF accuracy was fine in the 135-300mm range but a little unsure at 400mm.

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