Lens review

Sigma 17-50 mm f/2.8 EX DC OS HSM

6. Distortion

The combination of wide angle, good fastness and 3x zoom multiplier is a bit tricky when it comes to fighting distortion. It would be unreasonable to think the distortion could be negligible here. Of course it isn’t and the biggest problems we will encounter at wide angle where we noticed a significant “barrel” amounting to –3.47%. The deformations decrease very quickly with the increase of focal length and reach zero near 30 mm, where the level of distortion is just –0.08%. Immediately afterwards it changes the sign becoming pincushion and at 50 mm it reaches a not very bothersome value of 0.66%.

Although the result of –3.47% can’t be described as low, we must take into account the fact that the rivals don’t fare significantly better in this category. The Canon 17–55 mm f/2.8 at wide angle performed better, showing the level of –2.47%, but at the maximum focal lengths reached the values at the level of 1.5%. The Nikkor 17-55 mm f/2.8 at 17 mm had the distortion very similar to that of the Sigma (-3.39%) but at the longest focal lengths it was a bit bigger (at the level of 1%). We can say the results of the Sigma are typical for this class of equipment and definitely it shouldn’t be ashamed of them, especially compared to its more expensive competitors

Canon 50D, 17 mm

Canon 50D, 30 mm

Canon 50D, 50 mm