Viewfinder Markings While the KatzEye screen has no effect on the autofocus functions of the camera, when using any aftermarket focusing screen in the 300D, the AF indicator points will no longer light up in the viewfinder and the AF rectangles will not show. The lack of the indicator dots has no effect on the camera’s ability to autofocus and fortunately, all the functions of the AF dots are duplicated elsewhere on the camera - the LCD on the top will allow you to select your focusing point and the green light in the viewfinder will blink for focus confirmation. The KatzEye screen has only the prism circle and a hairline composition circle around the prism - many people actually find the cleaner viewfinder to be an advantage. But if you must have the AF indicators, your only option is to stick with the original screen.
Metering Information The split prism version of the KatzEye™ focusing screen for the Canon 300D does affect the light metering of the camera and will require you to use the exposure compensation adjustment of the camera (or manual settings) to get proper exposure. The amount of exposure compensation will vary between 0 f-stops with wide aperture lenses and 1½ f-stops with slower lenses. The expsure shift can be mitigated by using the Manual (M) shooting mode, which will force the camera to use centerweighted average (CWA) metering. CWA metering yields the most accurate results when using a split prism focusing screen. If you are not comfortable with using exposure compensation, either use the KatzEye™ microprism focusing screen or keep the original Canon 300D focusing screen.
The microprism version of the KatzEye™ focusing screen for the Canon 300D has the advantage of having no significant effect on metering, so exposure compensation will generally not be required.
The “Plus” Prism The KatzEye™ focusing screen for the Canon 300D is now available in the “Plus” version! The KatzEye™ “Plus” focusing screen for the Canon 300D is a laser matte with a split prism circle and a microprism collar. Due to the age of this model, no additional exposure testing has been done with the “Plus” version. It is expected that exposure results will probably be similar to the split prism version described above, but no guarantee is offered to that effect. Users are strongly encouraged to take test shots, check their histograms, and adjust the exposure compensation accordingly.
Like the other two KatzEye™ screens, the “Plus” version will have no effect on the autofocus functions of the camera, other than that the AF indicator points will not light up in the viewfinder - please see the Viewfinder Markings section for complete details.
Installation
Installation is not terribly difficult, but it does require care. Official instructions for the 300D are not available, as Canon never released a replacement screen. But, Michael Tan wrote instructions for the 300D which are available at 300D Focus Screen Removal Instructions.PDF. If you don’t feel confident installing it, your local camera shop should be able do it for around $65. Since the KatzEye screen is a direct replacement for the original, any competent shop should be able to handle the installation and the original screen can be reinstalled at any time, should you so desire. If you want us to install it at KatzEye™ Optics, we can, though it’s not the normal procedure. Please see the Installation Service page to order installation with your focusing screen. Installation service at KatzEye™ Optics costs $65, plus the cost of return shipping of your camera.
