Archived posting to the Leica Users Group, 1999/12/18

[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]

Subject: [Leica] Re: Re: full moon
From: George Huczek <ghuczek@sk.sympatico.ca>
Date: Sat, 18 Dec 1999 06:35:50 -0600

At 06:51 PM 17/12/99 -0700, John Collier wrote:
>The moon seems larger at the horizon as we can compare it to familiar
>reference points: buildings, trees, cows... High in the sky, without
>reference points, it seems to shrink. This is a psychological/optical
>illusion that is easily verified by using your thumb at the end of your
>extend arm as a reference point. Try covering the moon with your thumb when
>the moon is low in the sky and when it is at its zenith. Alas, how life's
>illusions fall away.

John has this right.  The moon appears larger at the horizon mainly because
it can be referenced against familiar objects near the horizon.  The
refractive effects due to the angle of light entering the atmosphere are
not as significant as they are with sunsets.

:::::::::
Julian's:

Techie, shmechie.  You guys have got me confused.  Does the moon *look*
bigger in a photograph taken with it near the horizon, as opposed to a
picture with it high in the sky?  Does it "fool" the camera like it fools
our eyes?  We all know, I think, that it isn't really bigger in size when we
view it in the different positions. But if it fools the camera, then this
illusion can be used to good effect in picture making.
- --->

It doesn't fool the camera.  It fools the brain.  It has to do with
perception.  Try taking a picture of the moon just at moonrise.  Then wait
a few hours and take it again higher up in the sky, using the same lens.
Enlarge the two images the same amount and look at the size of the moon.
It's size (i.e. relative magnification in the photo) is the same.
   Moons shot near the horizon are appealing, as Ted has pointed out,
because of the possibilities of including foreground.  Personally, I prefer
this than the double exposure trick used to make the moon appear grossly
out of proportion to everything else.