Monday, August 20, 2012

Shooting the Sky at Night


Taking a photo of stars is not difficult but it does require a tripod and you may have to look a little information up in your camera's manual (bummer). Also find a flashlight to take along. If you have one with a red filter or the option to use a red light that is best of all since the red light will not ruin your night vision. If you have a remote shutter release, take it along, but it is not necessary.

Next find a location away from city lights. Several miles outside of town and shooting in a direction away from town is best. It is nice if you can face an empty field so that a lot of sky is available.

The shot here was taken on a country road facing south. When I looked at the sky it was black except for the stars I saw no light at all. The camera saw the red/orange color along the horizon which I did not see.

Set your camera to it's manual mode, which is usually "M" on a round knob on top of the camera. Next turn off auto focus and manually focus your camera to infinity. The stars are too tiny for the camera to auto focus on. Find out how to set your camera's ISO and set it to 400.

Now you will need to check how to set the aperture and shutter speed. When you find out how to set the aperture set it to the smallest number you have. Probably something between 5.6 and 2.8. Remember that the smallest number is the largest opening, so we are letting in as much light as possible. Now find out how to set the shutter speed and set it to 30 seconds (see I told you you'd need a tripod).

Since your camera is in it's manual mode you may be able to do all of the above before you leave the house. Time is not critical but at least an hour after sunset is probably a good time to start. When you are in the field place you camera on it's tripod and point it in the direction of an interesting group of stars. In the photo above, if you're not a sky watcher, there is a group of stars about 2/3 of the way to the top and centered left to right that is a slightly sloppy rectangle of 4 stars and in the middle of the 4 is a diagonal line of 3 stars. This group is known as Orion and is a well-known winter constellation.

Now all is ready and all that is left to do is take the photo. Attach the remote release if you have it. If your eyes are good you may be able to check the focus by looking through the viewfinder. In any case press the shutter button very gently so as not to move the camera or if you have a remote release step back a little and press the remote. Stand still or walk gently away from the camera and wait the thirty seconds. If your camera has "long exposure noise reduction" and it is turned on you will now have to wait another 30 seconds while the camera makes a second 30 second exposure with the shutter closed. It finds out which pixels contain noise even without light and subtracts that noise from the image and keeps the noise level of the final image down.

After the 30 second exposure, and maybe the second 30 seconds, the image will appear on the cameras LCD screen and, if all has gone well, you will see stars. If you don't see as much as you hoped for you can try to increase the ISO to 800 or even 1600 if your camera allows it. Most digital cameras will not do an automatic shutter speed longer than 30 seconds and if you manually do a longer exposure you may start to see star TRAILS instead of stars. Nothing wrong with that some photographers do exposures of several hours or more to deliberately create longer and longer star trails.

Again: Have fun!


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