In article <330FEB75.7C90@ra.msstate.edu>, sgr1@ra.msstate.edu says...
[...]

> Angle of view (A) = 2*arctan(43.3/2*f)
>where f is focal length of lens & 43.3mm is the diameter I assumed of
>the image projected onto the focal plane.
>This formula indicated (A) of 84.1 and 75.4 degrees for the 24 and 28mm
>lenses respectively. I then made a chart of the corresponding field of
>views based on the angle of views. After that I decided to test the
>accuracy of the calculations with my 28mm. I set my camera up on a
>tripod and moved it in towards a door until only the door filled the
>frame of the viewfinder. The door was 36 inches wide. The camera was
>32 inches away from the door at the point that the door filled up the
>field of view. According to my calculations, the field of view at 32
>inches should have been 49 inches!!

Ah, but were you figuring coverage for the frame diagonal (84.1, 75.4
degrees, or for the (shorter) horizontal...? (And, as others pointed
out, were you allowing for the 10% or so of negative coverage not
shown in the finder...?)
Hope This Helps