Man, it's quiet out here.
I just had this conversation tonight about how beautiful my photos are. I have always had a love for the stars, well it started with dinosaurs but something from space supposedly wiped them out so go with the stronger right? I don't know it's always just been calming to me just watching the sky. I have always kind of been a loner in that way. I'm really not a fan of group activities. I used to be but something changed.
Now I would rather just sit in a field for hours with a camera pointed at a barn hoping the shot turns out alright, then taking another and another, and so on.
Anyone can do it, everyone seems to think that you need all this fancy crap to take pictures of the stars but it's really not the case. Just a camera with manual mode and tripod. Even if you don't have a tripod, just use some uncooked rice in a ziploc bag on the hood of your car works great.
Cameras control the amount of light taken in a picture by two basic ways. There is a shutter that opens and lets light hit the digital sensor in the camera, and there is a variable-sized hole, called the aperture or diaphragm, in the camera lens. If we leave the shutter open longer, we record more light. If we use a larger hole, we let more light in. Nothing complicated here.
Shutter speeds run in fractions of a second, usually around 1/1,000th of a second at the shortest exposure to many seconds at the longest. Most DSLRs also have a setting called "bulb" that keeps the shutter open as long as you press the shutter button down.
Aperture settings run in a crazy series of numbers like f/2.8, f/4, f/5.6, and f/8. Confusingly, the smaller the number, the larger the hole in the diaphragm. So, f/4 is a bigger hole than f/8.
Most cameras also have a way to change their "sensitivity". This is kind of a trick setting though. You can't really change the sensitivity of the sensor in the camera, but you can adjust a setting called the ISO, which is sort of like a multiplier factor. Some cameras can do 200-400 tops, some 12600, which is ridiculous.
Cameras like DSLRs, you can pre-focus the camera in the daytime on something very far away, and then turn the auto-focus off and gaffer the hell out of the lens so it is impossible to move(do at own risk) . If you have a DSLR with a lens that you can manually focus, focus it on infinity and tape it down. Beware, many of these lenses actually will go past infinity, so you can't just trust the markings on the lens that being said it is usually just before the infinity symbol.
Set the aperture on the lens. As you are trying to gather as much light as possible you may be tempted to set the aperture on your lens to its widest. If so you will be disappointed with the results. Starfields are very demanding of optical quality and camera lenses are not very good at dealing with them. As a start try the lens on its widest aperture, take a picture then look at the result by zooming in to your cameras screen. You will probably find that the stars are a little fuzzy. Now stop the lens down a couple of stops (i.e. from F2 to F5.6). Take another picture and check it again. You should see a marked improvement.
You also need to be aware that because of the Earth's rotation, the Stars appear to move across the Sky. Therefore the longer you keep the cameras shutter open, the more chance that you will get a star trail. (see below). However, the effect of star trails are minimised when using wide angle lenses. Below are approximate times before star trailing becomes visible for different lenses. I suggest you experiment and review your first images using your cameras LCD screen. Zoom in to see how much the star has moved. If its a streak and not a point of light, reduce the exposure time. You will soon get an idea of what length shutter speed you can get away with.
24mm - 20-25 secs
35mm - 12-18 secs
50mm - 6-8 secs