Canon 2376B001 camera lens adapter

Interchangeable focusing screens are a new and significant feature of the EOS 40D. The Ef-A Standard Precision focusing screen have a fresnel lens area and are produced by a new molding method (first used on the EOS-1D Mark III's focusing screen Ec-C IV) that provides excellent transfer characteristics. Consequently, even the Standard Precision Matte screen offers improved performance.