We all want to get excellent performance from our lenses, but even the very best glass requires a little helping hand in post-production. Martin Evening explains how
martin evening explains how to get the most from your lenses with some post-production help
We all want to get the best performance from our lenses. You can do so by selecting the optimum lens aperture for best image sharpness and careful focusing, but neither of these strategies can help you combat the effects of vignetting, optical distortion or chromatic aberrations. As with everything, you mostly get what you pay for. With the more expensive lenses you should expect to achieve more or less distortion-free results with limited vignetting, but even the best lenses can use some help at the image-processing stage to perfect the optical image quality.
When the Lens Corrections filter was first introduced in Photoshop, you could make manual slider adjustments to visually correct an image. This filter then got updated when Camera Raw and Lightroom introduced the concept of profiled lens corrections, which allow you to correct either in Camera Raw, or later in Photoshop. These days it makes most sense to apply lens corrections as early as possible in the image-editing pipeline. Therefore, when processing your raw captures it is best to use the Lens Corrections panel in Camera Raw. However, there are times (such as in the video file example on page 36), when the Photoshop Lens Corrections filter can still prove useful.
Correcting a raw image is mostly quite simple. All you have to do is open the photo in Camera Raw and click ‘Enable Profile Corrections’ in the Lens Corrections panel Profile tab section. Providing there is a lens profile in the Camera Raw database that matches the lens used to take the photo, Camera Raw automatically corrects the image. Lens profile corrections consist of two main components: a ‘Distortion’ correction to correct for barrel or pincushion geometric distortion and a ‘Vignetting’ correction to correct for light falloff toward the corners of the frame. When you apply
an auto lens correction to an image, the EXIF metadata information is used to automatically select an appropriate lens profile in the Lens Profiles section below. For this to happen the EXIF camera and lens metadata must be present. If not, you can manually enter the details in this section. If there are none available it may mean that Adobe have yet to add a lens profile for your lens to the Camera Raw database. But failing that, it is always possible to create your own (see ‘Creating your own custom profiles’ on page 37). Lens profiles can contain the information needed to correct for lateral chromatic aberrations, but Camera Raw now ignores such data. Therefore, when the ‘Remove Chromatic Aberration’ box is checked this applies a correction based on an analysis of the image, rather than referencing the profile data. The lens Corrections panel Manual tab controls provide backward compatibility, as well as providing controls to counter the effects of axial chromatic aberrations.
There aren’t any downsides to applying lens corrections to your images. The only time when you might not want to do so is if you wish to preserve the geometric distortion characteristics, such as when using a fisheye lens. Or, perhaps you might prefer the lens vignette darkening towards the edges of the frame? It is not just Adobe software that can be used to apply lens corrections. DxO was one of the first companies to offer lens correction controls using DxO Viewpoint.
Use the Lens Corrections panel in Camera Raw at the beginning of your raw processing workflow
Martin is a photographer with a commercial background in beauty photography. He is known for his in-depth knowledge of Photoshop and Lightroom and as an author on digital imaging. In 2008, Martin was inducted into the NAPP Photoshop Hall of Fame in Las Vegas. His recent books include Photoshop CC 2018 for Photographers and The Adobe Photoshop Lightroom Classic CC Book. Visit www.photoshopforphotographers.com.