Westminster fountain at sunset

by Jorge Córdoba

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Possible Duplicate:
Tips for landscape+stars photography?

I need some tips and tricks for photographing long star trails.

Some of the questions I am thinking about are:

What aperture/ISO?

If combining multiple shots, how do you avoid gaps in the trails, especially if the camera is taking NR "dark frames"?

How dark should it be so that the twilight doesn't wash out the stars?

If taking super long exposures(hours), will my battery run out mid-exposure?

How to balance the exposure of the foreground and sky

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marked as duplicate by John Cavan, ahockley, Matt Grum, mattdm, Rowland Shaw Jan 14 '11 at 8:01

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

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Ken, this has already been asked. See photo.stackexchange.com/questions/2136/… –  PearsonArtPhoto Jan 13 '11 at 14:11

1 Answer 1

When photographing stars, you can either get a star "field," a static snapshot of the stars as points of light, or star "trails," where the stars' movements streak across the sky. How long you expose the image determines which you get. The first rule of thumb to remember is that the Earth rotates such that the light from a star begins to "move" after about 15 seconds. It's apparent movement is largely dependent on your lens—the longer the focal length, the more apparent the movement; the wider angle lenses won't show much movement till later because of the star point is so small. For comparison, a close-up photo of the moon can only be about 6 seconds before the Earth's movement blurs it.

This is an extract from HERE.

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Doesn't the question specifically ask about aperture and ISO? (I also find it noteworthy that your source believes starlight is willing to sit still 15 seconds for the intrepid photographer, but not appreciably longer :-). If we were to engage about 6,000 people to train their cameras on the sky around the world, could we synchronize them to make the heavens stand still for an entire day?) –  whuber Jan 13 '11 at 23:17
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Photographing the moon with a telephoto lens will result in motion blur long before 6 seconds. With a very wide angle lens, you might be able to expose for about 5-6 seconds before motion starts blurring it. –  jrista Jan 14 '11 at 2:23

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