Correcting Lens Distortion

Next we'll tackle the chromatic aberration. Fortunately this too is fairly slight, and only red and cyan, which means that it too is easy to treat. It's easier to adjust if you zoom in on one corner . You can either use the zoom tool, or select the zoom level using the pop-up menu at the bottom left of the window. Move the image around in the window by holding down the space bar and dragging with the mouse.



As before, only a small adjustment is required, and only in the Red/Cyan slider. A change of +10 is sufficient to remove most of the chromatic aberration from the garden wall picture, while the fishing boat picture was corrected by an adjustment of -10. Clicking OK will confirm the Lens Correction changes and take us back to the main Photoshop workspace.



At this point we could crop the edges of the image and call it a day, but it is possible to go a little further with both of these pictures. The garden wall picture can be further straightened by using the Free Transform function, found in the Edit menu. By holding down the CTRL button the corner handles can be moved independently of each other to correct any remaining lens distortion or perspective problems. Drag guides onto the image to help get the corners square.



Meanwhile our boat at sea would benefit from a correction of the rather dodgy white balance imparted by the camera which was used to take it. Using the Levels (CTRL + L) function to set the sky as a white point instantly improves the whole picture.



All that remains is to crop out the untidy edges, save our newly edited picture under a different filename, and we're finished.

----