I don't *think* this is reciprocity failure...

I finally got a decent moon shot with my Tamron mirror lens:

http://www.flickr.com/photos/3585314...n/photostream/

I was using ISO 400, started at 1/400 and worked my way up to 1/800. The
histogram of the moon was clustered around the halfway point at 1/800, so I
was wasting some of the dynamic range, but that photo looked the clearest
so I went with it and messed with the "tone" curve to make the moon nice
and bright and contrasty. Maybe a little too contrasty. Couldn't seem
to fix the chromatic aberration in the Olympus program, and I am having
a bear of a time with Lightroom 3.6

Anyway, I went back out last night to get some pictures of a fat crescent
moon (~40%) and thought I would switch to ISO 200 to make it less grainy,
and shot at 1/200, 1/320, and 1/400 of a second. Halve the film speed,
double the exposure time, right? But for some reason that's not what
happened. The images were very underexposed, with the right tail of the
histogram barely reaching the midpoint at 1/200; the 1/200 images were
unusable for other reasons, but the others are so dark that I can't
reliably separate the "moon" from the "night sky" in the histogram.
Why would this be?

The Waning moon seems to have most of the mare (seas); could that be it?

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(Paul Ciszek) wrote in
:

I finally got a decent moon shot with my Tamron mirror lens:

http://www.flickr.com/photos/3585314...l/in/photostre
am/

I was using ISO 400, started at 1/400 and worked my way up to 1/800.
The histogram of the moon was clustered around the halfway point at
1/800, so I was wasting some of the dynamic range, but that photo looked
the clearest so I went with it and messed with the "tone" curve to make
the moon nice and bright and contrasty. Maybe a little too contrasty.
Couldn't seem to fix the chromatic aberration in the Olympus program,
and I am having a bear of a time with Lightroom 3.6

Anyway, I went back out last night to get some pictures of a fat
crescent moon (~40%) and thought I would switch to ISO 200 to make it
less grainy, and shot at 1/200, 1/320, and 1/400 of a second. Halve the
film speed, double the exposure time, right? But for some reason that's
not what happened. The images were very underexposed, with the right
tail of the histogram barely reaching the midpoint at 1/200; the 1/200
images were unusable for other reasons, but the others are so dark that
I can't reliably separate the "moon" from the "night sky" in the
histogram. Why would this be?

The Waning moon seems to have most of the mare (seas); could that be it?

A crescent moon requires more exposure than a full moon. You are simply
underexposing at ISO 200 and 1/200. Here is a calculator that gives you
approximate shutter speeds based on the other data you plug in.
http://www.adidap.com/2006/12/06/moo...re-calculator/

In article ,
Jeff wrote:

A crescent moon requires more exposure than a full moon. You are simply
underexposing at ISO 200 and 1/200. Here is a calculator that gives you
approximate shutter speeds based on the other data you plug in.
http://www.adidap.com/2006/12/06/moo...re-calculator/

Thank you!

--
Please reply to: | "If more of us valued food and cheer and song
pciszek at panix dot com | above hoarded gold, it would be a merrier world."
Autoreply is disabled | --Thorin Oakenshield

Jeff writes:

(Paul Ciszek) wrote in
:

I finally got a decent moon shot with my Tamron mirror lens:

http://www.flickr.com/photos/3585314...l/in/photostre
am/

I was using ISO 400, started at 1/400 and worked my way up to 1/800.
The histogram of the moon was clustered around the halfway point at
1/800, so I was wasting some of the dynamic range, but that photo looked
the clearest so I went with it and messed with the "tone" curve to make
the moon nice and bright and contrasty. Maybe a little too contrasty.
Couldn't seem to fix the chromatic aberration in the Olympus program,
and I am having a bear of a time with Lightroom 3.6

Anyway, I went back out last night to get some pictures of a fat
crescent moon (~40%) and thought I would switch to ISO 200 to make it
less grainy, and shot at 1/200, 1/320, and 1/400 of a second. Halve the
film speed, double the exposure time, right? But for some reason that's
not what happened. The images were very underexposed, with the right
tail of the histogram barely reaching the midpoint at 1/200; the 1/200
images were unusable for other reasons, but the others are so dark that
I can't reliably separate the "moon" from the "night sky" in the
histogram. Why would this be?

The Waning moon seems to have most of the mare (seas); could that be it?

A crescent moon requires more exposure than a full moon. You are simply
underexposing at ISO 200 and 1/200. Here is a calculator that gives you
approximate shutter speeds based on the other data you plug in.
http://www.adidap.com/2006/12/06/moo...re-calculator/

Okay, but *why* does it need a different exposure? The part that's lit
is lit by direct sun still.
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Photos: http://dd-b.net/photography/gallery/
Dragaera: http://dragaera.info

In article ,
David Dyer-Bennet wrote:

Okay, but *why* does it need a different exposure? The part that's lit
is lit by direct sun still.

I am ashamed that I didn't realize this myself: When the moon is a
crescent, no part of what you are seeing is illuminated "full on", by
sunlight perpendicular to the surface. You are looking at ground that
is illuminated by slanted sunlight, delivering less light per unit area
of ground. The angle that the ground makes to your line of sight may
figure into this as well, depending on the scattering characteristics of
the lunar surface.

--
"Remember when teachers, public employees, Planned Parenthood, NPR and PBS
crashed the stock market, wiped out half of our 401Ks, took trillions in
TARP money, spilled oil in the Gulf of Mexico, gave themselves billions in
bonuses, and paid no taxes? Yeah, me neither."

On 10/09/2012 19:12, David Dyer-Bennet wrote:
Jeff writes:

(Paul Ciszek) wrote in
:

I finally got a decent moon shot with my Tamron mirror lens:

http://www.flickr.com/photos/3585314...l/in/photostre
am/

I was using ISO 400, started at 1/400 and worked my way up to 1/800.
The histogram of the moon was clustered around the halfway point at
1/800, so I was wasting some of the dynamic range, but that photo looked
the clearest so I went with it and messed with the "tone" curve to make
the moon nice and bright and contrasty. Maybe a little too contrasty.
Couldn't seem to fix the chromatic aberration in the Olympus program,
and I am having a bear of a time with Lightroom 3.6

Anyway, I went back out last night to get some pictures of a fat
crescent moon (~40%) and thought I would switch to ISO 200 to make it
less grainy, and shot at 1/200, 1/320, and 1/400 of a second. Halve the
film speed, double the exposure time, right? But for some reason that's
not what happened. The images were very underexposed, with the right
tail of the histogram barely reaching the midpoint at 1/200; the 1/200
images were unusable for other reasons, but the others are so dark that
I can't reliably separate the "moon" from the "night sky" in the
histogram. Why would this be?

The Waning moon seems to have most of the mare (seas); could that be it?

A crescent moon requires more exposure than a full moon. You are simply
underexposing at ISO 200 and 1/200. Here is a calculator that gives you
approximate shutter speeds based on the other data you plug in.
http://www.adidap.com/2006/12/06/moo...re-calculator/

Okay, but *why* does it need a different exposure? The part that's lit
is lit by direct sun still.

Hold a tennis ball up at arms length in the sunlight and walk around it.
You will quickly see why the Earth-Moon-Sun angle matters.

The terminator is at sunset or sunrise with the sunlight hitting the
ground at near to grazing incidence. The same is true on the Earth
midday is a lot brighter than dawn or dusk with the sun low in the sky.

--
Regards,
Martin Brown

(Paul Ciszek) writes:

In article ,
David Dyer-Bennet wrote:

Okay, but *why* does it need a different exposure? The part that's lit
is lit by direct sun still.

I am ashamed that I didn't realize this myself: When the moon is a
crescent, no part of what you are seeing is illuminated "full on", by
sunlight perpendicular to the surface. You are looking at ground that
is illuminated by slanted sunlight, delivering less light per unit area
of ground. The angle that the ground makes to your line of sight may
figure into this as well, depending on the scattering characteristics of
the lunar surface.

Okay, that was one of the theories that crossed my mind. Some given
amount of sun is spread across a bigger surface.
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Snapshots: http://dd-b.net/dd-b/SnapshotAlbum/data/
Photos: http://dd-b.net/photography/gallery/
Dragaera: http://dragaera.info

On 9/9/2012 9:20 PM, Paul Ciszek wrote:
I finally got a decent moon shot with my Tamron mirror lens:

http://www.flickr.com/photos/3585314...n/photostream/

I was using ISO 400, started at 1/400 and worked my way up to 1/800. The
histogram of the moon was clustered around the halfway point at 1/800, so I
was wasting some of the dynamic range, but that photo looked the clearest
so I went with it and messed with the "tone" curve to make the moon nice
and bright and contrasty. Maybe a little too contrasty. Couldn't seem
to fix the chromatic aberration in the Olympus program, and I am having
a bear of a time with Lightroom 3.6

Anyway, I went back out last night to get some pictures of a fat crescent
moon (~40%) and thought I would switch to ISO 200 to make it less grainy,
and shot at 1/200, 1/320, and 1/400 of a second. Halve the film speed,
double the exposure time, right? But for some reason that's not what
happened. The images were very underexposed, with the right tail of the
histogram barely reaching the midpoint at 1/200; the 1/200 images were
unusable for other reasons, but the others are so dark that I can't
reliably separate the "moon" from the "night sky" in the histogram.
Why would this be?

The Waning moon seems to have most of the mare (seas); could that be it?


I like the esthetics of your result.

--
Peter