Steve - you have no idea of how accurately I work. On one of my enlarger I actually have a custom
focus telescope for magnifying the grain too, simply because the registered neg holder is about ten
feet above the vac easel, which is solid enough to stand on without deflecting it! Otherwise there are all kinds of potential issues, and they simply have to be isolated one at a time. Yes Bill, I have
seen grain magnifiers w/o front surface mirrors - they shouldn't exist, but do. And certain enlgr lenses are certainly capable of focus shift - one more thing to double-check. And to get a good idea
of the reprentative quality-control of a particular model magnifier, you'd have to compare dozens if
not hundreds of them. Just like buying a try square at the hardware store: bring along a true machinist's square and you'll discover just how very few conventional squares are really square!