Originally posted by stevebrot Issue? I seem to have missed that part of your post. As you are probably aware, microprism focus aids are more useful in the absence of hard borders, but are less sensitive to the OOF condition when doing fine work. As for the suggestion of the Ec-A, Canon warns that both split-image and microprism aids will interfere with spot-metering on their cameras. I personally, am not fond of microprism by itself, preferring split-image at center with microprism and fine-matte fields around that.
Canon Knowledge Base - QuickGuide to EOS Focusing Screens
Steve
Hmmmm. When I went directly from microprism on the Pentax K2 to split on the Pentax ME, I was never happy. Have no experience of split with outer microprism. Must admit, I mostly use spot metering, so if centre focus features (split or microprism) cause problems there, that would not be useful.
Got off my butt and used the forum search searching on "EC-A" which returned a large number of threads and posts.
As far as which is the more useful purely from a manual focus point of view, in this post:
Focussing screens for the K1 DIY split image - PentaxForums.com
the poster did say "Second update I changed the splitscreen for a microprisma screen that serve my needs better. (Canon Ec-A)
This set up is now used for a couple of shoots and I am 100% happy with it."
This comment is also interesting: "That being said, the matte area on the EC-A is
the best way to focus my f/1.2. I can reliably get spot-on focus from the impression using the matte area (I find microprisms more useful for quickly focusing, matte area for precision focusing). With the K3, there was simply no way to get reliable focus confirmation at 1.2"