Laowa 100mm F2.8 2x Ultra Macro APO

Distortions

Distortion refers to the capability of a lens to represent straight lines as... straight lines. Wide angle lenses often create barrel distortion, where lines look they've been put on a sphere. Telephoto lenses can create the reverse effect, named pincushion distortion. The following images illustrate the various types of distortion:

Barrel distortion, left; no distortion, center; pincushion distortion, right

It is very difficult to create a zoom without some distortion. It is also very hard to design a wide lens, even a prime, which is distortion-free. On the other hand, normal and short tele lenses can more easily avoid the problem.

The way to evaluate distortion is pretty straightforward: take a picture of straight regular lines, and look to see if they curve. Calculating the ratio of curvature yields an evaluation of distortion.

Distortion Test Results

The following images show how the distortion pattern looks when photographed with the Laowa 100mm, on full frame. There is of course no built-in correction tool in-camera for third-party lenses.

The amount of distortion is low, at -0.9% both with APS-C and full frame sensors. It will have a minimal impact in actual shooting conditions. Post-processing programs will take care of it without trouble.

Verdict

At -0.9%, distortion is kept under control, but still a bit high for a 100mm lens.