As a hobby, I re-take old photos and then produce an animated disolve between the old and new to show how the scene has changed over the past 50-150 years and then post them on the web. The trick is to determine where the original photographer stood when they took the shot and then frame it a closely as possible to the original.
Currently, I use a Canon Ti4 (but am lusting after an Olympus OM-D E-M1).
I'd love to be able to overlay a custom image on top of the image displayed in the viewfinder. I'm thinking this would make it much easier to re-frame the shots. Currently, I snap dozens & dozens of variations hoping that one is close enough to use.
Canon have a Windows utility that lets you control the camera from your PC via the USB cable. It has lots of features including the ability to overlay your own image over the app's viewfinder window and adjust the alpha. I'd love to have this feature onboard the camera.
Do any cameras have this ability?