a diopter won't be a complete solution if you have bad astigmatism and shoot both hor and vert.
HCBs first Leica did not have a rfdr.
with a 28mm I set it to six foot and use instinctive point all you need to do is float like Cassius Clay, think Brucie uses even closer range.
I also take up the first pressure on the shutter release
I skimmed the posts but I'm a bit confused.
I generally trust the viewfinders in my SLRs but I don't like using the split-image. I have little experience with them as I prefer matte but I do not trust them for critical focus.
To me, it sounds like you might make use of a rangefinder because the focusing on those things is binary.
The split-image screens are reliable, but you need a straight line or object at right angles to the split to take best advantage of them. I prefer a plain microprism dot myself. It really comes down to you, and what you're focussing on.
Originally Posted by msbarnes
I trust viewfinder focusing, I don't trust my eyesight because without them I can't even see the split image focusing screen on my cameras never mind focusing without my glasses, however I do have my eyesight checked every year and take my camera with me when the optician does the test to ensure my glasses have the right lenses in them, and I have no focusing problems.