>>2718018With the K-3 you can specify particular focus point too.
>>2718032A screen with microprisms or split hemispheres WILL interfere with light metering.
I strongly advise you to avoid those types.
My preference is for the completely bare - no markings - "high contrast" type.
http://www.focusingscreen.com/product_info.php?cPath=25_113&products_id=1108You can see if focus is achieved just as easily, much faster, albeint *slightly* less accurately, plus you arent constantly center-focusing and recomposing; which is a rookie mistake on wider planar-focus lenses.
http://pseudosticky.wikia.comand ctrl-F (search) for 'Petzval field curvature'
That said, I have largely gone back to the defalt K3 and K5 screens now, because frankly my f/2.8 lenses are much easier to use, offer attractive boke with sudden OOF falloff, and DOF depths that are actually useful at all distances, and are accurately auto or manually focused with no additional screen.
My advice is unless your lens if faster than f/2.8 don't bother, and if they are faaster then go bare, high contrast.
FYI: focusingscreens screens are cut from canon high contrast screens.
