I got the f/stops is f/stops part. That has to do with the surface
brightness on any given area of the film and screen. The mystery was
why the eyepiece brightness is not higher for the larger format.
Presumably the image magnficication through the eyepiece is less for the
larger format and should appear brighter?
Chuck Norcutt
Walt Wayman wrote:
> Well, not the best analogy I've ever come up with. The bottom line
> is, equal f/stops, no matter the format, come out the same in the
> end. If that were not so, then a scene you might shoot with a 35mm
> camera at 125th sec. at f/8, I would have to shoot at some different
> exposure with the RB-67. That's not how it works. The 50mm f/3.5
> Zuiko wide open admits light through a hole about 14mm in diameter,
> while the 127mm f/3.8 Sekor is pouring light through a hole a little
> over 34mm in diameter, which is probably admitting three or four
> times as much light as the Zuiko. (I'll leave it to somebody smarter
> tham me to do the pie are square calculations.) But, and this is what
> I was trying to explain before, the light coming through the bigger
> hole has to light up a proportionately bigger viewfinder AND,
> subsequently, expose a similarly larger piece of film. So, it's all
> the same in the end, 'cause f-stops is f-stops, for all practical
> purposes.
>
> I need more coffee to explain this any more better. :-[
>
> Walt
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