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

Discussion in 'Digital Photography' started by Paul Ciszek, Sep 10, 2012.

  1. Paul Ciszek

    Paul Ciszek Guest

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

    http://www.flickr.com/photos/35853148@N05/7960659668/sizes/l/in/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?

    --
    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
     
    Paul Ciszek, Sep 10, 2012
    #1
    1. Advertising

  2. Paul Ciszek

    Paul Ciszek Guest

    In article <XnsA0CA880C53D3jdonotspamme@209.197.12.12>,
    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/moon-exposure-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
     
    Paul Ciszek, Sep 10, 2012
    #2
    1. Advertising

  3. Jeff <> writes:

    > (Paul Ciszek) wrote in
    > news:k2jf8v$dmd$:
    >
    >> I finally got a decent moon shot with my Tamron mirror lens:
    >>
    >> http://www.flickr.com/photos/35853148@N05/7960659668/sizes/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/moon-exposure-calculator/


    Okay, but *why* does it need a different exposure? The part that's lit
    is lit by direct sun still.
    --
    Googleproofaddress(account:dd-b provider:dd-b domain:net)
    Snapshots: http://dd-b.net/dd-b/SnapshotAlbum/data/
    Photos: http://dd-b.net/photography/gallery/
    Dragaera: http://dragaera.info
     
    David Dyer-Bennet, Sep 10, 2012
    #3
  4. Paul Ciszek

    Paul Ciszek Guest

    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."
     
    Paul Ciszek, Sep 10, 2012
    #4
  5. Paul Ciszek

    Martin Brown Guest

    On 10/09/2012 19:12, David Dyer-Bennet wrote:
    > Jeff <> writes:
    >
    >> (Paul Ciszek) wrote in
    >> news:k2jf8v$dmd$:
    >>
    >>> I finally got a decent moon shot with my Tamron mirror lens:
    >>>
    >>> http://www.flickr.com/photos/35853148@N05/7960659668/sizes/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/moon-exposure-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
     
    Martin Brown, Sep 10, 2012
    #5
  6. (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.
    --
    Googleproofaddress(account:dd-b provider:dd-b domain:net)
    Snapshots: http://dd-b.net/dd-b/SnapshotAlbum/data/
    Photos: http://dd-b.net/photography/gallery/
    Dragaera: http://dragaera.info
     
    David Dyer-Bennet, Sep 10, 2012
    #6
  7. Paul Ciszek

    PeterN Guest

    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/35853148@N05/7960659668/sizes/l/in/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
     
    PeterN, Sep 11, 2012
    #7
  8. (Paul Ciszek) wrote:

    > 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.


    Just to address the question in the subject line, digital sensors don't
    suffer from reciprocity failure.

    Reciprocity failure is specific to film as it is caused by the fact that
    silver halide crystals need two photons in quick succession before the
    exposure registers. If the second photon arrives too late, the crystal will
    have already returned to the unexposed state, wasting the first photon. The
    dimmer the light, the more of it is wasted, hence the increasing loss of
    film sensitivity in darker conditions.
     
    Gordon Freeman, Sep 16, 2012
    #8
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. John Horner
    Replies:
    5
    Views:
    569
  2. cc

    reciprocity failure - what is it?

    cc, Jan 16, 2004, in forum: Digital Photography
    Replies:
    27
    Views:
    902
    Rudy Garcia
    Jan 18, 2004
  3. Reciprocity failure in digital camers?

    , Sep 12, 2006, in forum: Digital Photography
    Replies:
    6
    Views:
    622
    Alan Meyer
    Sep 19, 2006
  4. jimphotog via PhotoKB.com

    Reciprocity a problem with digital?

    jimphotog via PhotoKB.com, Mar 20, 2007, in forum: Digital Photography
    Replies:
    4
    Views:
    347
    jimphotog via PhotoKB.com
    Mar 22, 2007
  5. fashion t shirts seller
    Replies:
    0
    Views:
    1,570
    fashion t shirts seller
    Jun 13, 2011
Loading...

Share This Page