The Canon EC-1D Crop Lines Focusing Screen Set consists of two screens, one delineating a square format and the other a 4x5/8x10 format. The Crop Lines set, as the name suggests, is comprised of screens with the aspect ratio area marked with a thin border. The screens are based on the standard focusing screen for the 1D (Ec-CIII), but incorporate a crop line to aid in shooting to a fixed aspect ratio. Both screens are otherwise identical to the standard screen and no adjustment is required for proper ambient or flash metering.
Compatible camera models include EOS 1D, EOS 1D Mark II, & EOS 1D Mark II N.