Excellent - thanks much to all that replied.
You could print different ones such as a grid on transparent media with your computer printer. Cut them out and lay them as mentioned on the outer surface of the view finder.
Originally Posted by lxdude
^Yeah, what he said.^
Yup, just what you said. Boy we are a couple of smart fellas.
Anyone can make a Digital print, but only a photographer can make a photograph.