Viewfinder Markings While the KatzEye screen has no effect on the autofocus functions of the camera, when using any aftermarket focusing screen in the 10D, the AF indicator points will no longer light up in the viewfinder. 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 In our testing, both microprism and split prism screens seem to show a slight effect on metering. The effect will be most noticable in the Evaluative mode with the center point selcted and in the Partial metering mode. Metering shifts were observed to be between 1/3 and 2/3 f-stops, depending on conditions. The metering change is easily correctable with on-camera exposure compensation. It is advisable to always take a test shot and check the histogram to confirm proper exposure.
The “Plus” Prism The KatzEye™ focusing screen for the Canon 10D is now available in the “Plus” version! The KatzEye™ “Plus” focusing screen for the Canon 10D is a laser matte with a split prism circle and a microprism collar. The metering tests for the “Plus” version showed that when using lenses of f3.5 or better, no metering changes will be observed. With lenses that have a maximum aperture between f4.5 and f5.6, centerweighted average mode still shows no shift, but Evaluative mode and Partial mode will show a shift of 2/3 f-stops toward overexposure. These results are the same with or without the OptiBrite treatment. If you are doing true stop-down metering with manual lenses at apertures smaller than f5.6, it is recommended that you take a test shot and check your histogram to determine the necessary exposure compensation.
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 10D 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. The 10D is virtually identical, except for the fact that it has two tabs on the retainer which need to be released. If you don’t feel confident installing it, any local camera shop that does cleanings or repairs should be able install it for you. 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.
Brightness Enhancement
Like all screens made by KatzEye Optics, the 10D screen is available with OptiBrite brightness enhancement for the ultimate appearance. Click here for more information about the OptiBrite treatment. In the 10D, the OptiBrite treatment may cause apporoximately 1/3 EV change in the light metering.
