Focusing Screen Ee-S
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.
Offer valid April 1, 2015 12:00 a.m. through April 30, 2015 11:59 p.m. ET. Offer valid in U.S.A. only, and void where prohibited, taxed or restricted. Availability of certain items may be limited. Limit of ten of any one item per order, subject to availability. Order will be shipped to a street address in the 50 United States or the District of Columbia only. Dealers, distributors and other resellers are not eligible for this offer. Offer subject to Canon Online Store Terms of Sale.