Some of you have asked me what I do to take a picture of the Milky Way. I hope this helps. Taking pictures of the Milky Way is easy, but there are a few things you need to consider before going out into the night. Your tripod, camera body, camera settings, lenses and post processing are important things to consider before taking pictures of the stars.
Before anything else, set the camera to shoot RAW. You can set the camera to shoot RAW and JPG, but whatever you do, create a RAW file for the image. You have much more post processing capability with a RAW file than a JPG file. Make sure you get a RAW file.
The tripod should be stable. If you can avoid extending the legs, that will add to the stability. If there is a hook for weight, use the hook to hang weight to add stability to the tripod set up. If it is windy, try to set up out of the wind. Put the tripod on solid ground. If you are on rocks, everything can be moving every time you shift weight from one foot to the other. Use a timer and get away from the tripod and just let the camera do its thing. The basic goal here is to eliminate the tripod as a source of movement for the camera during the exposure. Unfortunately, a stable tripod usually equates to more money. I like carbon fiber. Put a heavy duty ball mount on the tripod.
Just about any DSLR camera can take a star picture these days. At a minimum the camera must allow you to manually set the focus, the ISO, the aperture and the shutter speed. I can’t speak to the digital point and shoot cameras.
When you get in the field you will need to focus the camera. Turn off your autofocus. Most cameras will not take an exposure in the autofocus mode when it can’t focus. The camera won’t be able to focus in the dark. Manually set your lens to “Infinity”. As a focus aid, I use a 5.0mW green laser to shine a spot on something a good distance away. Then I use “Live Mode” to optimize my focus on that spot.
You should shoot with the widest angle lens (widest setting for zooms) that you have in your kit. I like the 16mm setting on my 16-35mm zoom. Wide angle lenses allow you to shoot longer shutter speeds and not get star tracks or visible motion in the star image. At 16mm I can have a shutter speed of 15 seconds. At 80mm I can only have a shutter speed of 3 seconds.
The lens you use should be fast, the faster the better, because the faster lens lets more starlight get to the sensor. My 16-35mm lens is f/2.8 so it lets in a good amount of light. If your lens is f/4 or f/5.6 it will let in less light to reach the sensor. If your lens is f/1.4 or f/2.0 it will let in more light to reach the sensor. The faster the lens the better your results will be. I must clarify something about a fast lens. It may not be as sharp wide open as it is stopped down a couple of stops. So you may find that a 16mm f/4 is just as good as a 16mm f/1.2 that is stopped down to f/4, and costs one quarter the amount of the faster lens. So that is something to consider.
The shutter speed is dependent upon the focal length of the lens. A 15mm lens will let you set your shutter speed at about 15 to 20 seconds. I stay down at 15 seconds to minimize star tracks. There are formulas that you can crank through to determine what shutter speed you can use for what focal length lens. These formulas are easily googled on line. Or you can take a picture, zoom in on the image and see if there are tracks. If there are tracks, reduce the shutter speed. Find the shutter speed for your lens that will give you the tracks you can live with.
The ISO setting is the last adjustment you make to get the best image you can from your camera and lens. I shoot at ISO3200 to get enough light sensitivity to show stars. The problem with higher ISO values is noise in the image. With the camera set for lens, aperture and shutter speed, a lower ISO value may not pick up enough light to make an image. A higher ISO value may give an overexposure. So it is a balancing act to find the ISO value that gives the best results.
Let’s take a picture. To try and optimize your ISO setting, put on your widest lens, set the lowest F stop value the lens has, set the shutter speed at 15 seconds, set the ISO at 3200 and take a picture. Look at the image and zoom in to the maximum. Can you see star tracks? Do the stars look like small dots? Do you even see any stars or is the image white and washed out? Remember, this is just a starting point for reaching your optimum settings.
If you have star tracks that are short lines, change the shutter speed to a faster value. If the stars look like small dots, change the shutter speed to a lower value. You are adjusting the shutter speed to get the most light to the sensor with the desired amount of star movement in the image. Once you have the optimum shutter speed you can go back to the ISO setting.
If the image is overexposed, reduce the ISO value. If the image is underexposed, increase the ISO value. If your LCD automatically changes intensity when showing you your picture, you will have no idea if the image is over or under exposed. The image will always be presented at the same intensity through boosting or suppression. In this case you will have to bracket the shot and pick the best one in post processing.
High ISO values mean noise in the picture. Lower values mean less noise. Some cameras have more pixels, others have less. Some cameras have cropped sensors, others have full sensors. Some sensors are very sensitive and some are not so much. Some camera sensors have filters and some don’t. You just have to live with what you have, or buy a more expensive camera or a specific astrophotography camera. Your choice for how you want your star photos to look. For good star photos your sensor needs to be able to capture light.
Here are a couple of other tricks that might help.
Bring a red light. Most back packing headlamps have a red light. Red light has less effect on how well your eyes see in the dark. Light can be useful in the middle of nowhere.
Bring a bright light source for light painting your foreground.
Set the camera shutter timer to 10 seconds. This will give the camera/tripod system a chance to stop moving after you push the shutter button.
Set the “Mirror Lockup” function on. This will prevent the mirror from shaking the camera when it flips up and the shutter opens. With mirror lock up the mirror is up a long time before the shutter opens and that gives the camera/tripod system a chance to stop moving.
Buy a remote or cable trigger. This way you can trigger the shutter without touching the camera.
Set the “High ISO Noise Reduction” on. Not sure what this does.
Set the “Long Exposure Noise Reduction” on. The camera will take the picture and close the shutter. Immediately the camera will take a dark frame. The dark frame exposure is the same length as the first exposure. After the dark frame is done the camera compares the image to the dark frame and removes the hot pixels and some noise.
Get noise reduction freeware. Google and download what you like. There are many programs available.
Buy noise reduction software. There are many programs out there.
Use the RAW image processing software provided by your camera manufacturer or something like PhotoShop. Post processing lets you reduce noise, adjust colors and generally improve the raw image.
Well, that’s about it. Have fun and stay warm.
My real job is Quality Manager at a small, precision machine shop in Longmont, Colorado, USA. We do work for many large aerospace companies and we have machined parts for satellites orbiting the earth, the moon, and Mars. We also have parts landed and roving about the surface of Mars at this time. My goal with photography is to capture the beauty of the out doors world we live in. I prefer winter and mountain landscapes. Living in the west provides many different places to visit where the picture taking is wonderful. I really appreciate the Panoramio community and all the friendly members. What a wonderful concept. Thanks for visiting.