On Thu, 14 Jan 1999 10:49:42 -0600 (CST), "B.B. Bean" wrote:

>Thanks!

A couple of possible complications with the split-image
focus "aid"...: It appears to me that if the eye is decentered
in the finder eyepiece, in addition to the possible blackout
of one prism side (especially with slow lenses), one would
also see an apparent focus shift - and, the split-image would
have error unless the straight line of the subject is carefully
centered in the prism...
Perhaps someone would like to comment?