Quote Originally Posted by Paul Cocklin View Post
Bruce, not that it's any of my business, but I think you're flipping the image and then reversing it, and dpurdy is rotating the image. In both cases, left is right and up is down. What a crazy world we live in.
I'm not flipping anything. The lens projects an image that is both upside down and backwards. This is just simple physics. All lens systems do this, from the human eye to cameras.

The reason DSLR camera use a pentaprism is that to "correct" the image in the viewfinder they have to flip it twice -- once vertically, then again horizontally.