Archived posting to the Leica Users Group, 1997/09/24

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Subject: Re: 90/2.8--internal reflections
From: Eric Welch <ewelch@ponyexpress.net>
Date: Wed, 24 Sep 1997 09:35:19 -0500

At 06:21 PM 9/23/97 -0700, you wrote:
>> Since the moon is illuminated by direct sunlight, sunny 16 should give
>> an accurate representation, just as it does right here on good ol' ma
>> earth.
>
>That is my gut feeling until I begin thinking about light being reduced 
>by the inverse square of the distance.

The inverse square law doesn't apply to reflected from the subject you are
photographing. You'd think it would, but it doesn't. It only applies to
light from the light source to the subject. 

The sunny 16 rule does work for the moon as subject, but not moonlight (the
light between the moon to the thing the moonlight reflects off of. That's
subject to the inverse square law, just like light from your flash to
subject.)

=============
Eric Welch
St. Joseph, MO

 A modern fleet of ships does not so much make use of the sea as expoit a
highway. - Joseph Conrad