Photoshop Cropping – Is there a better way to crop out canvas and keep aspect ratio?

[RHCreative]

I shoot mainly architecture & interiors and deal with a lot of compositing of images. More often than not there's a little bit of canvas showing on 1 or more sides due to alignment of captures. Currently I manually crop all images just inside of canvas as each composition is a little different in terms of how much/where canvas is showig. This takes considerable time, is there a faster way to do this?

Is there a way to create an action for this?

[Mylenium]

If the empty area is consistent and not enclosed you can use the crop to transparency and similar functions from the menu and that could be automated with a keyboard shortcut and in actions.

Mylenium