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Lens review

Sigma 18-125 mm f/3.8-5.6 DC OS HSM

4 September 2009
Szymon Starczewski

7. Coma and astigmatism


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As you can see from the clippings of the diode below, coma makes life a misery at shorter focal lengths and vanishes almost absolutely for the range of 70-125 mm. It’s very similar to Nikkor 18-105 mm VR and slightly better than Nikkor 18-135 mm and Sony 16-105 mm, where coma influenced the shape of the diode for longer focal lengths as well.

Sigma 18-125 mm f/3.8-5.6 DC OS HSM - Coma and astigmatism

As far as astigmatism is concerned, we have no particular reasons to complain. It’s quite far from ideal, but 8% is a level definitely acceptable in this class appliance.