Thanks for the effort to answer.
And the 7D has a new metering system.
I am familiar with the 30D, 40D and 50D as I have each camera and Ikelite housing for each.
The difference in the viewfinder of the 7D as opposed to the 30/40/50 series is that the focus confirmation square in the 7D is a litle larger and it lights up in black as opposed to the smaller red square of the 30/40/50 series. In low light the entire focusing screen in the 7D will flash red to allow you to see better.
I will say this incorrectly, but the 7D has a digital viewfinder so that grids can be used as a part of the firmware of the camera.
Since the 7D focus confiormation square lights up in black, I am wondering if that is harder to see thatn the red square of the 30/40/50.
Hopefully someone that has this combuination and will care to comment.