I'm having a bit of difficulty interpreting the reflection, as my mirror is an old Pyrex with the 1/4" wide raised lip on the underside. It almost looks like this is messing with the clear reading of the edge at times. Your thoughts?
Exactly, I have a 6f9 on my tester and the reflections from the back are distracting. Not the raised rim, the smooth cast surface just inside of it... sort of an interrupted circle of light..wrecks subtle shadow and fringe interpretation. I'm ignoring it, but a light spraycoat of paint would help.