I've been getting a lot more into astrophotography and night photography lately, so I figured I would focus this post around that subject matter. Shooting long exposures can seem intimidating at first, but hopefully this post can serve as a jumping off point for beginners, and demystify the process a bit more for more mid range photographers.
Equipment: There are plenty of aspects of your night shooting that can be adjusted for the desired look, but in order to really get a workable image, you will need an SLR Camera, a tripod, and a shutter release. The tripod keeps the camera stable enough so that you can keep the shutter open for a longer (5s, 10s, 30s) exposure. While the camera is completely still, light information can pour into the lens, and allow for a brighter image. The shutter release will allow you to take the picture without shaking the camera by pushing the button while it's on the tripod. Although these three pieces of equipment are the most imporant, some honorable mentions would include...... a flashlight to help see your camera and where you're placing your equipment, a laser pointer to create neon doodles, some snacks to eat while your shutter is open, and some sandbags to hold the tripod in place.
Lens Choice: Usually with star photos, youll want to shoot on a wider lens. Something in the 14-35mm zone would be preferred, but you can still get decent results with a slightly longer lens. The wider your aperature (lower Fstop number), the more light the sensor will pickup from your lens. I find that once you get down to about the 4.0 zone, each little increment buys you a pretty solid amount in not only depth of field, but also in low-light clarity.
Environment: If you're specifically focusing on star/ Milky Way photos, you'll definitely want to check the weather report before going out. The lunar cycle is definite consideration when shooting star photos. If you're strictly shooting the sky, then you'll probably want as little light pollution coming from the moon as possible. You may want to go out during a new moon, or a crescent, especially if you are trying to get the Milky Way. If you're shooting more than just the sky, and you want to have some compositional elements, props, etc in the shot, I find that a full moon can create a very interesting lighting effect during a long exposure, but it'll be harder to pickup on some more distant/faint stars.
Composition: When it comes to taking photos in the dark, you always want to compose your shot during the day if you can. it's much easier to find a composition in broad daylight, than try to guess and check when its nearly pitch black outside.
Camera Settings: Once you're all setup, and you've composed your shot, you'll want to dial in your settings. The lower the Fstop (aperature), the more light you'll be letting in. While shooting in low-light settings (like night photography), usually you want your Fstop set to the lowest number possible. Keep in mind, this will create more depth of field, so make sure to be focussed properly on the night sky. Generally auto-focus wont work in low-light, so I suggest changing your focus to manual, and rolling it all the way to the infinity symbol, meaning you're focussing super far away. Your shutter speed and ISO will also be huge factors in a longer exposure. the higher your ISO, the brighter your image will be, but that brightness comes at the cost of graininess. Usually, I aim for a middle range ISO somewhere in the 400-1000 zone, with an exposure around 5s-15s. If my image is too dark, I can lengthen the exposure, or crank up the ISO. The balance between your big 3 (Fstop, ISO, Shutter Speed), is what will get your shot to come out clearly. Side note: If you want star trails, youll need to keep the shutter open longer, which means you may have to compensate by turning down the ISO. Conversely, if you don't want star trails, you can have a shorter exposure time, and crank the ISO up a bit higher. Additional side note... the longer your lens, the more prominent your star trails will be.
Editing: It's easy to shoot lots of photos on your camera and never get around to editing them. That being said, editing is an important part of developing your skills as a photographer. Taking your shot from start to finish will help you assess the attributes of different shooting styles. It's also fun to be able to finish working on a shot and share your work with other people.
Here are a few samples. Let me know if you have any questions.
Joshua Tree: ISO 2000/ f4.0 Exposure:30s (All settings are fairly high to pull out the milky way from the dark sky)
Downtown LA: ISO 2500/ f4.0 Exposure:1/3s (high ISO allows for a relatively short exposure)
Santa Monica: ISO 200/ f22 Exposure:8s (higher Fstop produces the star effect seen above)
Camera, tripod and (nearly invisible) shutter release