Correcting distortion and other common lens errors can be a real chore. In this tutorial we show you a few simple ways to use Adobe Camera Raw and Photoshop’s Lens Correction filter that can cut your photo editing time down significantly.
Creating the perfect lens isn’t easy or cheap, and as a result most lenses, even very expensive optics aimed at professional photographers, produce images that benefit from a little correction.
Wide-angle lenses, for example, are known for their tendency for barrel distortion – so called because straight lines begin to bow like the wood planks in a barrel.
Meanwhile, telephoto optics are more likely to suffer from pincushion distortion. This is where straight lines appear to be much closer together in the middle of the frame than they are at the edge.
Vignetting, the darkening of the image corners that can be a plus or a minus point depending upon the shot, can be another issue, especially at very wide apertures.
Chromatic aberration, which occurs when a lens fails to focus the different colours that make up white light at the same point, is another common problem. It results in red/magenta or green/cyan fringing along some edges.
It tends to be most noticeable along high contrast edges towards the corners of the frame. Tree twigs and branches against a bright sky often exhibit the problem.
Photoshop affords two useful methods of correcting these optical flaws. The first is found in Adobe Camera Raw, while the second is the Lens Correction filter within Photoshop itself.
Whichever of these methods that you choose, we strongly recommended making the corrections before any other transformations are applied. Now let’s take a look at what’s involved.
Adobe Camera Raw Lens Corrections
The easiest way to correct the optical problems associated with a lens is to apply an adjustment profile found under this tab. Once a tick is placed in the Enable Lens Profile Corrections box, the software checks the image EXIF data to identify the lens that was used to capture it. If there is a profile, it automatically applies the necessary corrections.
The manufacturer’s name and model appears in the drop-down boxes, so that you can verify if the correct one has been used (or select another). If you click on any of these boxes, you can see the alternative options that are available.
This tab was added with the upgrade to Camera Raw 7.1, and it’s where those nasty magenta and cyan fringes that can appear along the high contrast edges in an image are removed. Selecting small coloured areas to adjust would be very time consuming, but in most cases all you need to do is put a tick in the Remove Chromatic Aberration box in the Color section of Camera Raw’s Lens Corrections area.
If necessary, the Amount slider can be used to apply more hardcore removal, while the Hue control allows fine-tuning of the colour of the fringing that is targeted.
When there isn’t a profile for the lens that you took your shots with, you can use the Distortion control in this area to correct the barreling or pincushioning that it creates in an image. The Lens Vignetting slider is also available to address any corner shading issues.
The other controls in this tab allow you to correct aspects such as keystoning, heightened perspective and rotation that are a feature of the angle that the image was shot from.
Meanwhile, the Scale slider allows you to quickly resize the image to take account of any of the adjustments that you’ve made.
PAGE 1: Adobe Camera Raw Lens Corrections
PAGE 2: Apply vignetting with the Lens Correction filter or ACR
PAGE 3: Correcting dramatic distortion with the Lens Correction filter or ACR
PAGE 4: Fixing chromatic aberration with the Lens Correction filter
[syndicated from Digital Camera World]