I am out in Colorado with the new 30D. I am looking to finally get some good star pictures this time. I am planning on using the 17-40. I have a shutter release and tripod. What settings should I use? I am probably be going to try it Monday and later as it is snowing right now.
My night shots are shot in Manual mode usually Iso 100/200 shutter times varry in the effect your looking for up to 30 seconds timed or the bulb setting.
Shoot on the wide end of the lens, so you will be able to get longer exposures. At 50mm, shooting towards the eliptic, your slowest shutter speed would be about 4 seconds, before your stars turn into smears due to rotation of the earth. At 8 seconds, you will notice some streaking if you pixel peep.
Therefore, when shooting at the eliptic, (where apparent rotation is fastest) limit yourself to:
2 sec. @100mm
4 sec. @50mm
8 sec @24mm
16 sec @ 12mm
If you are aiming to the north or the deep south, you can double or even triple those times. For example shooting in the direction of Polaris, you can probably get away with a 12 second exposure at 50mm, simply because the star movement is so slow.
If you have access to Photoshop, you will want to process them.
I have found that the best method is to use a high ISO, like 1600 or 3200, and then shoot 8 shots one immediately following another, without moving the tripod.
These shots can be blended together in photoshop easily to average out the noise and to sharpen the details.
Here is a single image, notice the noise! 50mm f/1.8 ISO800 4 seconds. 100%
Now, look at a composite of 8 frames, all blended together in photoshop. 100%
The dimmest stars you see are Apparent Magnitude +8 to +9. Orion is close enough to the elliptic to show trails at anything more than 4 seconds. I could have used higher ISOs, but this was the look I was striving for. Less orange glow in the pictures...
Shooting with higher ISOs and longer shutter speeds will allow hot pixels to show up in your frames. Expect to deal with them, once you have your composite finished. Before they are fixed, your composite will show this...
Nope! That isn't an airplane! You line up the images, by the star positions, and that makes the hotpixels appear to travel across the sky like stars. Cleaning them up at the end is easy.
Also notice some flaring off the brightest stars such as the one around Saiph (bright star at the bottom of the sword of Orion). I was shooting wide open with the lens, which hurts quality in favor of brighter images. The farther from the center of the image you get, the more flare you will notice.
Hopefully I will be able to get out tonight and try this again. Last year did not go so well.
Hmmm. It looks like you are using a cable release in the second pic, right? If you are going to get star trails, go ahead and REALLY let that shutter stay open a while.
If you are anywhere remotely near a town, you'll get orange glow in the sky. Using the lowest Kelvin temp setting on your White Balance will make that glow less orange, and your stars will be bluer.
Those aren't bad pictures.
The best way to get some really awesome sky images is to use an equatorial mount and an electric drive. This will allow the camera to track the stars, and allow you to use insanely slow shutter speeds.
I once stumbled across a website that had plans for an inexpensive do-it-yourself mount, that used 2 pieces of wood, a piano hinge, and a threaded bolt. The hinge points at Polaris, and joins the pieces of wood so that it looks like a book. The bolt goes through the book and is secured in such a way so that as it is turned, the book opens and closes slowly.
Some math is required to determine how fast the bolt should be turned to keep pace with the sky. Turn the bolt some amount every so many seconds, and the camera that is mounted to the wood, follows the stars... I sure wish I still had that website.