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Lens review

Sigma 12-24 mm f/4.5-5.6 II DG HSM

27 December 2011
Arkadiusz Olech

10. Autofocus

The Sigma 12-24 mm II is equipped with an ultrasonic HSM autofocus drive. Small wonder the mechanism works noiselessly and is quite fast. Running through the whole distance scale takes about 0.5-0.7 of a second which is a good result.

It’s worth remembering, though, that the combination of wide angle and average fastness imposes such a significant depth of field that in many situations the tested lens’s autofocus is simply redundant. For example while working on full frame at 12 mm, even when the lens is wide open, it’s enough to set the distance scale at 1.1 meters to enjoy a sharp image in the range from 0.55 of a meter to infinity. For a change at the maximum focal length and the maximum relative aperture setting the sharpness at 3.5 meters gives you a sharp image from 1.7 meters to infinity. When you take photos with the aperture stopped down significantly the depth of field becomes so big that the autofocus can be practically switched off completely.

It all makes the analysis of the autofocus accuracy almost unnecessary. Such a large depth of field forgives you even big mistakes. Because of that, the mechanism’s efficiency is very good and in studio conditions we didn’t notice any misses.


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While working on both bodies, used in the test, so the D200 and the D3x we didn’t observe any front or back focus tendencies.

Sigma 12-24 mm f/4.5-5.6 II DG HSM - Autofocus

Sigma 12-24 mm f/4.5-5.6 II DG HSM - Autofocus