http://blog.wired.com/gadgets/2008/06/gallery-of-cut.html

This is pretty neat.

Regards, Art.

Well, now I know that digital SLRs don't have real pentaprisms. Another thing to hold against them. :)

I think that must be a Sony.

They have a mini sensor at the top of the pentaprism, and the main mirror moves slightly if you want to use the screen on the back instead of the viewfinder, sending the light to this sensor isntead of the viewfinder.

They do still have a proper pentaprism which is only used when in 'normal mode'