When using the Transform tool to correct perspective in Camera Raw, the resulting image is often cropped in order to avoid displaying blank areas around the edges. To help retain necessary information from the original image that would otherwise be cropped use the Scale, X Offset, or Y Offset slider in the Transform panel to reposition the image within the canvas.
In the illustration below, after applying the Full Upright mode to correct perspective in Camera Raw, the image on the left was scaled to 90% using the Transform panel (revealing the transparent areas around the edges of the image). The image on the right is the result of opening the image in Photoshop, selecting the transparent areas and then filling them using the Edit > Fill with Contents set to Content-Aware.
