Originally posted by Groundloop I've not seen any 3rd party grid screens for Pentax (or any other DSLR/SLR) for that matter. Only bright screens or split prism screens.
I ordered the LL-80 Divided Matte screen (aka The Grid) when I ordered my K10D. Unfortunately it took over 3 months to arrive! Anyway, I've used grid screens in all my cameras since the mid 80's. In addition to helping you line up horizontal and vertical lines, I find they help me to judge the relative sizes of objects in the frame, so as to avoid "That looked bigger in the viewfinder" syndrome.
And for what it's worth, I find manual focus a little easier with the LL-80
Why bother with 3rd party screens. The Pentax LL80 divided matte cost me all of C$40.50.