I've just changed out the focus screen in my camera from the standard matte one to a KatzEye split prism screen. So, pictures for anyone who's interested. I've used it for about a week so far. Swapping out the screen took less than five minutes and seems to have gone in okay first time. It does make focussing on objects within a scene easier at the cost of a little underexposure depending on the lighting. Some shots have been unaffected, some seem out by half a stop, although it's easily corrected. Although... since I put in the screen, it's been overcast and surprisingly dark outside anyway. The AF is untouched as that part of the system is before the focus screen anyway. KatzEye tool, box and DVD for scale. I went for the OptiBrite treatment and Pentax AF brackets. The focus screen is the standard Pentax one as the KatzEye was in the camera at this point. I had taken pictures with an FE-115 during the install, but they didn't come out very well. However there's plenty of videos on YouTube showing people changing the focus screen. K-x with Sigma 18-50 F2.8, taken with a Canon PowerShot S5. KatzEye unfocused/focused. The actual image is a little darker than that, but I couldn't stop Canon over-exposing the images. IRL, the centre split is more pronounced. K-x with the DAL 18-55 F3.5-5.6 kit lens. One half of the split image gets a slightly darker around 5.6 depending on lighting conditions. Automatic lenses don't stop down until you take the picture, so a 2.8 at 11 will be 2.8 through the viewfinder. Pentax K100D with the standard Pentax focus screen and the Sigma lens for comparison.
It's still pretty dark outside, so I'm not sure about the true effect on metering. Some shots I took shortly afterward seemed to vary between okay and a little underexposed, although I'd rather have images in focus and play about with the levels in PP than the other way round. MF seems to be spot on and the prism helps see which part in a scene you're actually focussed on in AF mode. Overall, I'd say it's worth it, but it's pretty expensive. With OptiBrite and Pentax focus marks, the one screen came to: $200 + $67.73 shipping + £41.42 import and tax to th UK = £218.61 There is another site, www.focusingscreen.com that is slightly cheaper and does different variations of split prism, including the Nikon K-3 that KatzEye seems to use. There’s a thread on the Pentax forums showing user reviews for each one: http://www.pentaxforums.com/forums/camera-studio-accessories/77151-focusing-screen-reviews.html
