keytarjunkie
no longer addicted
You can get a split-prism screen for the 7D. Katzeye sells one for $160 with their special low-light brightness enhancing magic powder stuff. Or $105 for just their regular screen with a split prism, which I'm sure is still pretty good.
http://www.katzeyeoptics.com/item--Canon-7D-Focusing-Screen--prod_7D.html
You can look up reviews...Katzeye screens are generally really good quality. The stock DSLR focusing screens are set up for all those slow f/4-5.6 zooms to keep overall brightness levels up...these are more for faster f/1.2-f/2.8 lenses and increases ease of focus for them. At least with the cheaper screen I bought (Canon makes a similar product which is good), if you stop down past f/4 the viewfinder will be noticeably darker than with the stock screen. Most of the time we aren't interested in DOF preview though so it doesn't matter to me! It might to you.
Having a split prism greatly increases the accuracy of focusing, especially with lenses 50mm and longer on a APS-C camera.
http://www.katzeyeoptics.com/item--Canon-7D-Focusing-Screen--prod_7D.html
You can look up reviews...Katzeye screens are generally really good quality. The stock DSLR focusing screens are set up for all those slow f/4-5.6 zooms to keep overall brightness levels up...these are more for faster f/1.2-f/2.8 lenses and increases ease of focus for them. At least with the cheaper screen I bought (Canon makes a similar product which is good), if you stop down past f/4 the viewfinder will be noticeably darker than with the stock screen. Most of the time we aren't interested in DOF preview though so it doesn't matter to me! It might to you.
Having a split prism greatly increases the accuracy of focusing, especially with lenses 50mm and longer on a APS-C camera.