Lens Corrections in AfterShot and How To Make Your OwnAlex Brazeau
Many advanced photo editors allow you to correct various optical imperfections found in camera lenses. Don’t think your favorite (and probably rather expensive) lens needs a correction profile? Well, you may not have noticed these issues a first glance, but you’d probably be surprised to find out these defects are common across all lenses.
So… what can you do to fix them? Read on to learn a little more about lens profiles like why they’re needed, how to apply them and how to create your own lens corrections in AfterShot Pro 3.
What is a Lens Correction Profile?
All camera lenses create distortion in photos ranging from perspective distortion, chromatic aberrations, and vignetting at the edges of the image. Lens profiles counteract these distortions and, like any other setting in AfterShot Pro, can be applied non-destructively and as part of a batch to hundreds of photos at once.
One of the most important things to know is that lens corrections are not universal. Each one is unique and specific to an individual lens. On top of that, each lens profile needs to be optimized for each model. The profile for a Canon 50mm f/1.8 will be different than a Nikon 50mm f/1.8 and you can’t apply one just because they’re similar.
If you want to experiment with using different lens corrections, the AfterShot team maintains a database in AfterShot Pro 3 that’s updated on an ongoing basis. Let’s take a look at how to apply a lens correction profile from the database to an image in your library.
How to Apply Lens Corrections to an Image
Applying a set of lens correction to your photos is incredibly easy to do. AfterShot and AfterShot Pro 3 comes packed with a database of pre-calibrated lens correction profiles for all kinds of popular lenses from camera manufacturers like Canon, Nikon, Fujifilm, Sony, Panasonic and lots more!
To get started, select any RAW photo from your collection. Once selected, head over to the Detail tab (found along the right-hand-side of the AfterShot window) and scroll down to Lens Correction.
You’ll see that with the RAW image selected, the Lens Correction area is now lit up, meaning it can be accessed (note that you’ll need to use RAW images to apply lens corrections as JPEGs do not store the information required to make the adjustments).
The next step is to select the lens you used from the AfterShot Pro database. If your lens is in there, AfterShot Pro will recognize it automatically thanks to the Metadata that gets stored alongside your image when your camera takes the picture. If for some reason your lens does not automatically populate, you can always browse through the database to see if it’s there.
To start your search, click on the drop down menus to choose the Manufacturer, Camera Model, and the Lens. Once each of these has been selected, you will also need to enter the Focal Length at which the shot was taken.
If you’ve been using a fixed-length prime lens, this is pretty easy (like a 50mm), but if you’re using a zoom this could be a little more troublesome. If you’re not sure what focal length you used, this information is usually stored in your image’s metadata. To reveal these hidden details in AfterShot Pro 3, just click the Metadata tab.
Next, adjust for any chromatic aberration you see in the image. You’re looking for colored fringes around edges of objects in your photo, like in the sample photo below.
Photo by Darron Birgenheier
Now click the checkbox next to Chromatic Aberration to enable the correction and use the slider labeled R/C to adjust the red channel to remove red or cyan fringes. you can also use the B/Y slider to get rid of any blue or yellow fringes you see.
Last step is to correct any vignetting caused by the lens. You can adjust the Strength of the vignette (how bright or dark it is) by moving the slider left or right. Same with the slider for Radius, which adjusts the feathering of the vignette.
Create Your Own Lens Correction Profiles in AfterShot Pro
There are literally thousands of lenses on the market, so sometimes the one you’ve got in your kit bag may not be in the AfterShot database. In this case, you can simply create your own lens profiles using the manual calibration tools, found by clicking the tab marked Manual in the Lens Corrections area under the Details tab.
Before you start, you’ll need to find a photo that will make the lens distortions easier to see. Photos with strong horizontal or vertical lines often show lens distortion.
Here’s an example of an image that would work well for creating a lens profile.
For a straight lines reference, go ahead and activate a crop grid by clicking the Crop tool.
At this point, if you notice your image is tilted, click on the Straighten slider under basic adjustments, or click on the straighten tool (next to Crop), then check the Enable Correction box to show your changes.
With your image straightened, it’s time to correct the actual distortions caused by your lens.
Start adjusting the following controls to correct the distortion (listed in suggested order). You will need to experiment with the settings to get the exact effect you want.
- 2nd order — often used to correct Pincushion distortion
- 3rd order — often used to correct Wavy distortion (also known as Moustache distortion)
- 1st order— often used to correct Barrel distortion
QUICK TIP: If you’re using a mouse with a mouse wheel, the easiest way to adjust the values is to click the arrows to the right of the number box for the control and use the mouse wheel to adjust the values.
The rest of setting up your profile unfolds the same as it would if you were applying a profile from the database. Adjust for chromatic aberration using the R/C and B/Y sliders to remove any fringing, then move on to correcting the vignette with the Strength and Radius sliders.
When you’re happy with the lens correction results you’ve applied, click Save. Click Yes, and give your XML file a name. These profiles can be adjusted at any time by loading them up using the Load button. Sometimes fine-tuning can be an ongoing process.
Have you created your own lens correction profiles or have tips for the community? Share them in the comments below!