Eclipse of the Moon

Michael A. Covington wrote:
"Jean-David Beyer" wrote in message
...


3.) The moon reflects about 250 cd/ft^2, so your exposure might as well be
1/250 second using an aperture equal to the square root of your film
speed, or equivalent.

Say your film speed is ASA64. Square root of that is 8, so an exposure of
1/250 at f/8 would work. You need not stop down anymore because how much
depth of field could you need with something a quarter million miles away?
And opening it up should not be necessary because you should not need more
shutter speed.


Impressively accurate! But those calculations, alas, are for the uneclipsed
moon...

So what? Since the moon has, according to most sources, no atmosphere,
there will not be a lot of diffraction of the sunlight, so the exposure of
the part still illuminated by the sun will be the same. Naturally, if
there is a total eclipse, you will photograph nothing in any case.

I.e., changing the illumination of one part of the subject does not affect
the illumination of the rest, and does not change the required exposure.

With a digital camera set to ISO 200, my exposures at f/10 were about 1/125
during penumbral phases, up to 2 seconds during the outer part of totality.
I'm not trying to photograph deep totality.

Of course, but unless your digital camera had a spot meter in it, small
compared with the 1/2 degree size of the moon, and pointed at the
illuminated part, its exposure will be wrong (overexposed) to begin with
and worse as the eclipse deepens.

See: www.covingtoninnovations.com/michael/blog (October 27 entry).

I'm doing very similar film photos, but of course they aren't developed yet
A digital camera makes an excellent exposure meter for difficult
subjects.

If you say so. I would not.


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In article ,
Jean-David Beyer wrote:
Michael A. Covington wrote:
"Jean-David Beyer" wrote in message
...

3.) The moon reflects about 250 cd/ft^2, so your exposure might as well be
1/250 second using an aperture equal to the square root of your film
speed, or equivalent.

Say your film speed is ASA64. Square root of that is 8, so an exposure of
1/250 at f/8 would work. You need not stop down anymore because how much
depth of field could you need with something a quarter million miles away?
And opening it up should not be necessary because you should not need more
shutter speed.

Impressively accurate! But those calculations, alas, are for the uneclipsed
moon...

So what? Since the moon has, according to most sources, no atmosphere,
there will not be a lot of diffraction of the sunlight, so the exposure of
the part still illuminated by the sun will be the same. Naturally, if
there is a total eclipse, you will photograph nothing in any case.

I.e., changing the illumination of one part of the subject does not affect
the illumination of the rest, and does not change the required exposure.

If the moon's surface receives less illumination because the earth is
blocking the sunlight, then the moon will be darker, and more exposure will be
needed. Also, in total eclipse the moon is still illuminated by sunlight
diffracted into the earth's shadow by our atmosphere. It's really
a strange sight to see the quiet red moon among so many stars in such a
dark sky, and allows us for a moment to look at familiar things as though
they were new.

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kind regards, --travis Rage, rage
my opinions only against the dying of the light