the Ee-S Super Precision focusing screen is designed to facilitate manual focusing with high-speed lenses (f/2.8 or faster). The Ee-S screen has finer microlenses than the Ee-A or Ee-D options, along with a steeper parabola of focus to make the image pop in and out of focus more vividly in the viewfinder; however, the Ee-S focusing screen is not recommended for slower lenses because it's not very bright.
One reason why the Canon Ee-S is popular is because of its Easy to use.
|Canon Focusing Screen Ee-A (Precision Matte) for EOS-5D Digital SLR Camera||$34.95|
|Canon Focusing Screen Ee-D (Precision Matte with grid) for EOS-5D Digital SLR Camera||$34.95|