Thanks all!
GemBro...
The diffuser was exactly as shown in the last picture I added to this posting:
http://www.photomacrography.net/forum/v ... hp?t=17656
Except I used two fiber optic light guides for the illumination instead of the Ikea lamps. (The 50X needs a lot more light than lower magnifications).
The "list price" for the Olympus 50/0.50 LMPLFLN is about 10% less than Mitutoyo 50/0.55.
(These were older numbers from memory... checking Edmund Optics they are now selling the Olympus for about $220 more than the Mitutoyo
. But you can find these pretty regularly used at much lower prices). Also... the results from a 50/0.50 or 50/0.55 objective can look very good on a screen, but in a large print or at 100% pixel peeping don't expect to see the fine detail you will see with something like a 10/0.28 or 10/0.30.