The Lens Correction page contains automatic and manual lens correction
controls as well as perspective correction features.
Profile
The Profile tab sheet mainly contains controls for automatic lens correction with the exception of the two sliders at the bottom. Lens correction consists of three different operations: optical distortion correction, vignette reduction and chromatic aberration removal. Lens profiles contain hidden values for these three corrections based on previous measurements. So a lens profiles is used to perform lens correction for a certain lens model.
The Enable Lens Profile Corrections check box has to be active in order to apply the automatic distortion removal and vignette removal. If it is not active, the controls below this check box have no effect on the image.
The Remove Chromatic Aberration check box automatically removes the tiny colored outlines, also called fringes, in the corners of the image that are produced by lower quality lenses. To see this effect you have to set the zoom to 400% or higher and scroll to one of the four corners of the image or even better click with the zoom tool on one of the image corners. However, if you opened an image that does not contain any colored fringes, you will see no change at all. If some colored fringes are still left after activating this check box, you can manually remove them with the Defringe controls that are located on the Manual tab sheet and explained below.
The Setup combo box offers various options. The Default and Auto options have the same functionality at the moment, which may change in a future update. Both choose the lens profile that is automatically detected. The Custom option is automatically selected if you change one of the three Lens Profile combo boxes or one of the two bottom slider, so you do not need to select it manually.
The three Lens Profile combo boxes let you choose a lens make, lens model and a matching lens profile.
Sometimes you may want to exaggerate or weaken the automatic lens correction for creative purposes. Then the Distortion and Vignetting sliders let you adjust the intensity of the automatic lens correction. If both sliders are set to 100, the lens correction is performed with the hidden values of the selected lens profile. If you think the correction is too severe or weak for the current image, you can use both sliders to adjust it to your taste. The Distortion slider increases the distortion removal intensity with slider values above 100 and decreases it with slider values below 100. At a slider value of zero you get the original look without any lens distortion removal. The Vignetting slider also lets you increase the vignette removal strength with higher values than 100 and decrease it with lower slider values. At a slider value of zero no vignette removal is applied. Vignetting is the circular darkening of the image borders by the lens.
Manual
The Manual tab sheet offers controls for further adjusting the automatic lens correction. But these controls also work if you have completely deactivated automatic lens correction (as well as deactivated the Remove Chromatic Aberration check) on the Profile tab sheet or if no matching lens profile is available.
The Distortion slider tries to remove the distortion of wide angle lenses with positive slider values and compensate the distortion of telephoto lenses with negative slider values. As this correction is based on a general mathematical model it may work fine with many lenses but may not completely eliminate the distortion of some lenses.
The Defringe controls let you remove chromatic aberration (colored fringes) in the corners of the image. Unlike the Remove Chromatic Aberration check on the Profile tab sheet these controls let you treat severe fringes more effectively. Colored fringes can be visible as green/purple outlines around tiny details like tree branches or bricks, but the colors can also vary to red/cyan or yellow/blue. To see the fringes you have to set the zoom to 400% or higher and scroll to one of the four corners of the image or even better click with the zoom tool on one of the image corners. If your image does not contain any colored fringes you can skip this step. The Defringe feature does not work in Photoshop Elements 11 and requires at least Camera Raw 8.7 in newer versions of Photoshop Elements.
The Purple Amount slider lets you remove fringes with a warm color like magenta, red, orange or yellow. The Green Amount slider on the other hand removes fringes with a color color like green, cyan and blue. Try to avoid too high values for both slider otherwise you may produce gray details, which do not look that great. The Purple Hue and Green Hue sliders each offer two handles for defining the color range that is affected. If the color fringes do not vanish completely you can extends or shift the color range defined by one or both sliders to improve the effect. But again if you make the color range too wide you may get gray details even at lower Amount slider values.
The Amount slider of the Vignetting controls brightens the image corners for positive slider values and darkens them for negative ones. The Midpoint slider determined how intense the vignette effect is applied to wards the center of the image. Higher Midpoint slider values reduce the vignetting in the image center while lower slider values extend the effect more towards the center. As this vignette removal effect is modeled after a mathematically perfect circle it may work fine with some lenses but may still retain some slight vignetting for other lenses.
Geometry
The Geometry tab sheet offers features for fixing the perspective of photos. The Upright combo box contains options for automatically correcting skewed object lines in photos. The Off option deactivates the auto correction. The Auto option performs all available automatic correction methods. The Full option makes vertical and horizontal lines straight in the photo whereas the Horizontal and Vertical options only do that for horizontal or vertical lines.
The seven available sliders let you manually correct the perspective or geometry of the photo. The Vertical and Horizontal sliders correct the perspective in each of these two dimensions. The Rotate slider rotates the image up to 15 degrees in each direction. The Aspect slider lets you adjust the image proportions and the Scale slider allows sizing the image, e.g. to remove transparent areas. The two Offset sliders move the image horizontally and vertically in case some parts of the image are moved out of the view.
The Constrain to Image check box crops away transparent areas that resulted from the above adjustments.