Got wiser yesterday...
I finish a long distance call of about an hour Finland to US, here is
what we talked about...
Those brighter screens are brighter, yes and no... Most of the screens are
"tuned" for F2.0 and working well from F1.4 to about F2.8. The thing he does
is to tune them to F2.8 to F5.6 or F8 to F..
I ordered the clear SD-11 and a matte SD-21 both we be repolished to
remove any marking and made as a bright for F4 to F8. If I like the job I
will send him another set to tune at F8 to F11.
These new screens without any marking of prism will be very difficult
to focus at F1.4 to F2.8 but when using DOF or F4 lenses will become as
clear than a lense at F2 with the current focus screen.
Now the next step for me will be to get a split center and the same
process applied, this should bring the following advantages, "OK" Focus for
fast lense using the slip and clear view when using slow lenses or DOF.
Anyway this is just speculation, but so far all the medium format guys
pointed me at him for my project. Most of the astro photographer eard his
name somewhere. I guess Ill give him a shot.
Oh yeah I forgot I plan on using that with a F10 1500mm mirror lense
with probably 1 or 2 TC, that's why...
His information:
Maxwell Precision Optics
P.O. Box 33146
Decatur, GA 30033-0146
Tel: 404-244-0095
Fax: 770-939-6644
Warning he will talk to you and check your needs before selling to you, and
that can be "long"
Philippe
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