LensTip.com

Lens review

Sigma 85 mm f/1.4 EX DG HSM

20 December 2010
Arkadiusz Olech

10. Autofocus

A Canon mount version of the lens arrived to our editorial office as first. We attached it to the EOS 1D Mk IV and tested the work of its autofocus. Already at the very beginning we noticed the right mechanism calibration because the lens focuses at the right point precisely and didn’t have any front or back focus tendencies. The Nikon mount version worked exactly as well – the lens on the D3x was very accurate. We also haven’t noticed any problems when working on the D200 model which lacks any autofocus micro calibration.

The Sigma features an HSM mechanism so the autofocus should have been noiseless. Unfortunately it is not the case – from time to time you can hear not very loud “squeals” while working on the 1D Mk IV and it’s difficult to determine their nature without disassembling the lens. What’s interesting, though, we didn’t hear these “squeals” in the case of the Nikon mount version model.

The speed of the focusing mechanism while the lens is cooperating with the Canon camera is beyond reproach. Running the whole scale takes about 0.7-0.9 of a second which is a good result. On the D3x the lens seems to work a bit faster because running the scale takes about 0.5-0.6 of a second.

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When it comes to its accuracy we don’t have any serious reservations here. The number of misses in studio conditions reached the level of 5% after attaching the lens to the Nikon D3x camera. It is perhaps not a negligible value but you shouldn’t worry about it either.


Sigma 85 mm f/1.4 EX DG HSM - Autofocus

Sigma 85 mm f/1.4 EX DG HSM - Autofocus