Help with star/night photos.

[RBennett]

Does anyone have any tips or suggestions on how to take star shots? I am wanting to start trying to get some star pictures and didn't know where to start. Living in city limits I am going to have to drive a half hour to get to where it is dark enough and wanted to have a plan of attack. :thumbsup2

[YesDear]

Just remember that when it is night time here it is daylight on the star. This may sound strange as well but remember that the earth is moving.

You did not express if you were trying to get a sky full of stars or the very long exposure to get the star trails. Gdad posted some really good ones here in the past year. They take about 10-15 minutes.

Let us know exactly what you are trying to do!

[RBennett]

Sorry, I was trying not to ramble (like I usually do) and guess I didn't explain more. I am actually wanting both, star trails showing the movement AND stationary.

[disneyboy2003]

Star trails are pretty easy. Just place your camera on a tripod, set your shutter speed to "Bulb" mode, and fire away. Do you have a remote control shutter? That would likely help prevent camera shake. You'll get good star trails after several *minutes* of exposure. That's why you'll need to be in "Bulb" mode. My wife was totally bored watching me take photos of star trails. :sad2:

Regular star photos are a little trickier. If you can't autofocus on any one star, then set your focus to infinity. Open your aperture as large as possible (do you have a large-aperture prime lens, like a 50mm f/1.8, 50mm f/1.4, 30mm f/1.4, etc?). You might have to use higher ISO, like ISO 400-800. For shutter speed, I saw the beginnings of star trails at around 15 seconds...for sure 30 seconds has visible star trails.

There's lots of trial and error, so see if that works.

[tlcmommyx4]

When doing star trails, do you have to have your camera in MF or can it still be in AF? I tried to get lighting from a storm and put on bulb and couldn't get anything?

[Gdad]

For long exposures a tiny bit of ambient light goes a long way- the light that made the nearly blown out areas in the bottom of both frames is the nearest small town maybe 20 miles away and not even visible to my eye when I took the shots. It gets to be a real problem for me since I don't live anywhere near any truly dark skies so my next venture is going to give a try at time lapse shots merged together.

Also keep in mind the longer the lens the less time you can leave the shutter open before the stars begin to 'trail' in the image. The rule of thumb formula for how long you can make your exposure and still get sharp points of light instead of blurs for stars is 600 divided by your focal length. The more zoomed in you are, the more slight motion blur becomes an issue (unless of course that is the look you are going for...) So in the examples below 600/14mm=42 Seconds Maximum.

44 Second exposure, ISO 1600, 14mm, f2.8.
http://farm3.static.flickr.com/2801/4340436882_b1f8c87eb8_b.jpg

32 Minute exposure, ISO 200, 14mm, f8.
http://farm5.static.flickr.com/4051/4339692941_5825f47d4c_b.jpg

[VVFF]

I learned the hard way that extremely long shots get VERY noisey. Yes, even at ISO 100 a 40 minute shot will come out noisy. I posted the shots and asked what was up. The response was that low noise star trail shots are done by stacking multiple shorter exposures. Just something to keep in mind.

[handicap18]

Another thing to remember when doing star trails is that for most entry level and some mid level dSLR's you are limited to 30 minutes for how long the shutter can be open in BULB mode. Check your owners manual for what your camera restrictions are.

The longer the shutter is open the more curve you get with the trails.

Its fun to experiment. Give yourself LOTS of time, especially if you use the Noise reduction feature on your camera. When you do a 30 minute exposure, the NR will also take another 30 minutes.

[rtphokie]

A way to control noise, and over exposure (especially in light polluted areas) is to limit exposure times to 5 minutes and then stack them up to get longer trails. If you are handy with Photoshop, this is a pretty simple process. There are a number of standalone programs that will do this for you as well, ImageStacker (http://www.tawbaware.com/imgstack.htm)is inexpensive and does a good job.

In short

low ISO (100-200)
long exposure (many minutes)
light pollution is your enemy unfortunately
open the aperture as wide as possible



If you'd like the get the circular effect in the star trails, aim towards Polaris or the north star. The Office of Naval Research has a nice tutorial (http://www.onr.navy.mil/focus/spacesciences/observingsky/constellations3.htm)on finding it.