Remember, light falls off with the square of the distance. For instance, if I
take a photograph of, say, the cat lying by my feet from a distance of four
feet, then I move back and take another shot from eight feet, only half as much
light reaches the camera and comes out through the viewfinder at eight feet as
did at four. But the cat looks exactly the same, because the image is only half
as big, so half as much light spread over half as much area looks, and
measures, the same. Obviously the converse would be true: twice as much light
spread over twice the area would be the same intensity.
If a larger viewing surface could cause the image to be brighter, then an 8x10
view camera's ground glass should look like a plasma TV screen. It don't, as
anybody who's sweated and muttered profanities under a focusing cloth can
attest.
Walt
--
"Anything more than 500 yards from
the car just isn't photogenic." --
Edward Weston
-------------- Original message ----------------------
From: Chuck Norcutt <chucknorcutt@xxxxxxxxxxx>
> Thanks. This is about what I expected would happen in the first place.
> The only problem is that I can't explain why.
>
> Chuck Norcutt
>
> Walt Wayman wrote:
>
> > Okay. All you had to do was ask. :-)
> >
> > The cameras: OM-4Ti with 2-13 screen, Mamiya RB-67 with regular
> > split-image WL viewfinder The lenses: 50/3.5 Zuiko Macro, 127/3.8
> > Mamiya Sekor C (Don't have a 3.5 lens for the Mamiya, but I figured
> > this was close enough.) The light source: 13x17 in. slide viewer at 1
> > ft. The measuring device: Sekonic Digi Master L-718 meter using the
> > ground glass probe The difference: OM-4Ti 2/10 stop brighter, or just
> > about what you might expect to be the difference between f/3.5 and
> > f/3.8. As the mythbuster guys would say: BUSTED.
> >
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