Thursday, July 31, 2008

Star Trail

What do you first think when you look into these photos? Are they computer generated effects, or probably some graphic designed background? These are called Star Trail.

Star Trail is generated by some simple photography techniques. 3 most important aspect to be emphasized, which are ISO, Shutter Speed and Aperture. I haven't tried to take this photo before, but I could provide some basic general information on how Star Trail can be taken. However, this really require a more advanced camera.

First thing first, normal compacts would not be able to take this photo due to its limited control on these 3 main components. Therefore, a DSLR would be needed. Then, of course, for its perfection, additional accessories like a remote control, etc would be good for the enhancement of the photo.

"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 30-40 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.) Part of your experimentation will be to gauge the timing for how much "trail" you want.

Photographing star trails is technically simple; the main things to keep in mind are:
  • Timing the light

  • Compositing the scene

  • Watching battery power

  • Experimenting a lot
Most people who get started with shooting star trails want to capture the longest trails they can by keeping the shutter open longer. The inherent problem with this is underestimating the ambient light in the sky, even though you don't necessarily see it. This light may come from nearby cities, or even the diminishing sunset an hour or more afterwards. What your eye sees is nothing compared to a long exposure of a camera, where this residual light can be so overwhelming, you don't see any stars at all. A 20 minute exposure an hour after sunset can look like a day shot, and if the moon is anything more than crescent, you'll be limited to just a few minutes at best. (By comparison, a full moon will make a night shot look like a day shot in about 8-10 minutes at f2.8 at ISO 100.) Picking a faraway place on a night with a new moon (or where the moon hasn't yet risen, or after it's set) is best for getting the darkest skies, which make the light from the stars is more pronounced. This may not be as easy as you think. The photograph of the lit tents shown here was shot in Death Valley (over 300 miles away from Las Vegas), which still had an illuminating effect on the horizon. To illuminate the tent, I spent about 30 seconds waving a flashlight around from inside the tent. This process is hard to get right without overexposing the tent's fabric. Again, the benefits of experimentation. This light also helped bring out detail on the ground." - Adapted from

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