Advice on calculating exposure times on night photos

Discussion in 'Beyond the Basics' started by pcdavis, Jun 21, 2004.

  1. pcdavis

    pcdavis TPF Noob!

    Jun 19, 2004
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    I will be in Yellowstone and would like to take some night photos showing star trails. I'll be shooting with velvia 50. I know there are a host of factors that will affect the exposure times, but does anyone have any good resources or tips for night time photos.



  2. Cuervo79

    Cuervo79 Guest

    dant 50 in the dark, that makes it more dificult, try 5 10 or 15 minute exposures, although that would get you a little bit of movement if I am not mistaken...
  3. malachite

    malachite Heavily Medicated For Your Protection

    Feb 23, 2004
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    Not in Arizona anymore

    Use slide film for the most error free results. I generally only use f/5.6 or f/8 with 100ISO film to stay consistant. For the best star trails make sure you're not out on the half of the month with half a moon or more. With no moon, go atleast 15-20 minutes for pronounced star trails. Stop down a bit to f/8 or f/11 an go for 30 minutes to an hour or more.

    There's a few variables that only personal experience can teach but that should get you started. If you've got the north star in view, expose on the longer side to get the most motion. If the north star is to your side, you'll get enough trail to go almost clear across a 50mm lens in about an hour. Too long and the trails start merging and the effect gets too much.

    My experience is based on being far away from city lights and shooting slide film, getting the best results with super saturated films like Velvia and Ektachrome SW or Fuji 64T tungsten film. Only other universal bit of info I can lend is make sure the batteries stay fresh in your camera. 2 or 3 half hour exposures in a camera that relys on battery power to keep the shutter open and the mirror up will kill the batteries quick so bring spares if you plan on being out for awhile or the camera will shut down, closing the shutter and dropping the mirror prematurely or they won't close at all until you put in fresh batteries.

    If you had some specifics with the what and where, I could give you a little more specific advice.

    EDIT - OK I actually read your post this time so I got the where and slide film thing this time :? Your biggest factor is going to the the phase of the moon when you're there. That's what makes it all happen and determines how you shoot. So when exactly are you going to be there taking pics?

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