Originally posted by bilybianca Second experience: It's a very discouraging exercise to manually focus an f1.4 lens with the original Pentax matte focusing screen. I thought something was wrong with my otherwise stellar A* 85mm 1.4 lens, so many shots were slightly out of focus. When I read
this thread and bought another screen from Taiwan it brought new life to the fast lenses. So if you go the fast lenses lane, consider getting the Canon EE-s screen too.
Changing screens may mess with the metering, and may make slow lenses hard to handle.
Like so much in photography, it's a tradeoff.
I don't have the A* 85/1.4, but do have the cheaper (!) Zeiss ZK 85/1.4, as well as a Voigtlaender 58/1.4.
Personally, I'm able to focus them both
with a mixture of focus confirmation/CIF, stock viewfinder screen interpretation, and live view.
It does depend on practice, eyesight, and so on.
Strangely enough, I find to easier to focus this way with the APS-C K-x
than I ever did with the microprism screen in the FF film Spotmatic.