When taking exterior photos it is often necessary to tilt the camera up in order to get the whole house in the frame.
The problem with this is tilting the camera causes a perspective warp in the image. The vertical lines in the shot are not parallel. It will be necessary to stretch the top of the image outwards so the lines are parallel again. It is useful to use guide lines when fixing perspective. To make a vertical guide line just click and drag from the ruler on the left of the screen. If rulers aren’t turned on just use the short cut “command+r” to make them visible.
Now that we have our guide lines close to some large vertical lines for reference we can start transforming the image. Using the move tool, click on the transform control on the corner of your image. Then right click on the image, selecting perspective from the drop down menu of transformation options.
Now you can click and drag on one of the top corner controls and drag away from the center. Drag until the perspective is corrected. It might take a couple tries with zooming in and adjusting the vertical guides. After you have adjusted the vertical lines you might have noticed that the house looks squished vertically. To fix this just stretch the house out a little bit on the top or bottom. It is useful at this step to compare your edited image to the original image. Below is an animated gif showing a before and after. I hope you found this tutorial useful and hope it gave you a new perspective on photographing exteriors.