A different type of straightening

A perspective straighten is very useful manipulation for some situations where you cannot find a enough room to get back from your subject (a window or large painting across the room or a building across the road). With a wide angle you will get diagonals running in several directions. The edges may even be noticeable curved. Lightroom now has a Upright command to do this under the lens correction menu. I assume it is doing a fair bit of distortion transformation mathematics, but it can do a good job providing the distortion isn’t too large (and perhaps it needs to recognise the lens). I have found a marvellous alternative in a plug-in for AfterShot Pro called zPerspector which achieved much the same transformation via a set of four sliders that independently adjust the sides/quadrants of the photos. With a little experiment it is easy enough to fix even extreme diagonals. You can also use the plug-in to create your own extreme perspective.