Re: finders - hacking solutions anyone?

[GAPiccagli@xxxxxxx]

In a message dated 8/29/00 11:07:50 AM, rsage@xxxxxxxxxxxxxxxxxxxx writes:

<< 1) Homemade wire-frame non-optical viewfinder with rear sight and front
frame that may even fold down out of the way. >>

An interesting idea. I'm wondering what the design parameters are:
1) front part of the finder should have the aspect ratio of the format
2) rear part should operate to center the eye,
but how is the distance between front and back related to 
a) the focal length of the objective, and
b) the dimension of the front opening?

Anybody have a cache of formulas to keep us from having to think too hard?

Thanks.

Wide Giorgio
Expansively in San Francisco