Originally posted by Eruditass I've heard its the most consistant way to expose. That and the loss of the focus brackets as my only indication of focus point indication are the only thing keeping me away from a split-image focus screen, whic I really wanted.
I dislike focusing aids in the middle of my focusing screens, and love grid lines so that my trees are standing straight. I began with a plain matte screen (first Pentax ever built) and used it for some 15 years which certainly helps. All three camera bodies in my signature have matte grid screens in them. I find that trying to line up the two halves of a prism on a moving bird is not as easy as it seems, and, as you say, costs some metering accuracy because of blackouts.
The system for manually focusing with a matte screen is to first make sure that your diopter is exactly correct. If you cannot see the in focus point, you are lost. I use the lines on the screen to set the diopter eyepiece, others use the LEDs.
There are those that rely on the focus indicator at the bottom of the screen (the green hexagon) but I find this is not a good method when there are contrasty things not quite where the focus should be - such as a bird in a tree. The focus indicator will prefer the branches.
The manual focusng method I use is to rock the point of focus back and forth over the subject. The first while you will be going back and forth a lot, but should be able to get it, with practice, down to past one way, back past the other way and return to the focus point. This is with a clear subject in good light, of course. The O-ME53 1.2X eyepiece on my k10 helps quite a bit, but I used my k10 for over a year without it. I got one for a birthday present, and it does make it a bit easier.