Make lens corrections

Fix lens-induced artefacts such as vignetting, distortion and chromatic aberration

even the most expensive lenses can add geometric distortion to a photo.

As light is focused through a lens onto the sensor, it can cause horizontal and vertical lines to bulge (or barrel) outwards in the photograph. In most cases this geometric distortion is subtle and you’ll only notice it when toggling the correction on and off (see our video lesson).

Different amounts of light may enter the lens at the edge of the frame. This uneven exposure can cause the edges of the photo to become vignetted and appear darker than the rest of the image. Vignetted edges are especially noticeable in clear patches of blue sky, as we see in our example image.

While geometric distortion and vignetting can be quite subtle, other lens-induced artefacts can prove to be more unsightly. When different wavelengths of light fail to focus on the same part of the sensor it can result in ugly fringes of purple or blue clinging to contrasting edges. Fringing tends to be more noticeable when using kit lenses, though expensive lenses are not immune.

Digital Photo Professional 4 lets you correct subtle geometric distortion such as barrelling. It can also remove unwanted colour fringes and lighten up vignetted edges to create a more even exposure.

Unlike Adobe Lightroom or Photoshop, Canon’s free app lacks the tools that can counteract converging verticals caused by perspectival distortion, but it will do a good job at removing colour fringes. This can make a huge difference in the quality of your picture.