Canon EF-S Matte Focusing Screen For Canon 40D, 50D

This Ef series Super Precision Matte Ef-S Interchangeable Focusing Screen from Canon offers easier focusing through the viewfinder. This screen is an "S"-type, which means it works by decreasing the focus of the slightly out-of-focus areas around your in-focus subject for a sharper contrast. The Ef-S screen provides precision focusing even in low light.