Just to follow on from the last post, here’s an example of how perspective control can be used to tidy up a photo: I was shooting derelict buildings in Derby and even with a 24mm lens had to tip the camera up to get it all in. The result was a shot where the building appears to be leaning backwards, with noticeable converging vertical lines. Some people like this effect, but for this shot I wanted to have the building depicted “correctly”, i.e without any distortion. I shot the photo with quite a lot of extra space around the main subject, knowing that I was going to crop it later.
Once I’d loaded it into Lightroom I simply went to the Lens Corrections palette and use the Vertical and Horizontal transform tools to straighten it up. Finally I added a very slight Rotate adjustment, made a few changes to the exposure and contrast, and the job was done.
After examining the shot for a while I realised that it was impossible to completely straighten the image as the building itself is wonky!