Perhaps my biggest surprise on my first visit to Africa was the night sky. I expected a lot of stars, I just didn’t expect THAT MANY!
As a boy, I grew up in a rural area, away from city lights. This allowed me to look up to the sky and see many things: meteor showers, the occasional satellite, airplanes from distant locations flying over and, of course, the Milky Way. I always loved that night sky and whenever I am in remote locations I make a special effort to enjoy my re-visit to this childhood memory.
On my first trip to Africa, I happened to be in the bush on a moonless night. As are most July nights in Africa, it was also very clear and cloudless. This afforded me a fantastic sky. I even picked up my binoculars to look even deeper into the nighttime. This was special, but I believed that this could only to be a memory as I didn’t think my camera would be capable of properly capturing that sky. Yes, I knew I could do long exposures and create star trails (these will be the subject of a future article), but what I wanted to capture was that special sky just as I was seeing it … with all of the twinkling lights and the special colors that only peering into the center of a galaxy could yield.
Upon returning home, I started an internet investigation as to what equipment was needed to do astrophotography. It turns out that really all one needs is a modern dSLR, a tripod, a cable release and knowledge of how to set up equipment. It helps to have a “fast lens”, but this isn’t a necessity.
Let me summarize a few points.
- You do not need a telescope.
- You do not need a tracking mount.
- You do not need a long focal length lens.
- What you need is a dark location away from city lights
- What you need is a lens that will allow the composition you desire and will allow you to set an f-stop that is f4 or faster.
- What you need is a way to stabilize the camera for exposures up to 30 seconds. A tripod and cable release are best, but a timer and a beanbag will actually do.
- What you need is a camera that will allow you to shoot at least ISO 800. To my knowledge, every dSLR since 2005 will allow this. The newest ones allow ISO settings of 3200 and higher. Normally one worries about sensor noise at higher ISO, but this will be less of a problem with sky photography.
How to photograph the African night sky
The following is a step by step summary of what I learned:
- If you plan to create a composition with a foreground (trees, mountains, etc. are a foreground when shooting the deep sky), set up your tripod while it is still light and you can see the area you plan to shoot. If you are planning to “just aim up”, this step isn’t necessary.
- Set up your tripod while it is still daylight
- Set the ISO at a high setting. I am told 3200 is great; however, I still didn’t believe the reading that noise wouldn’t be a problem, so I used 1600 and it was fine.
- Set your camera to shoot in RAW. This is needed to allow optimized post processing.
- Set aperture at an open setting. f2.8 is great, but f4 will work. Remember, we are trying to let all of those little twinkling points of light into our camera.
- Fire away with exposure times as a function of focal length as follows:
|Focal Length||Shutter speed|
You may be wondering why the shutter speed varies. An over simplified explanation is that the earth is rotating (duh) and you want to have the stars round and not egg shaped or streaked. As the focal length gets longer, this emphasizes the problem not dissimilarly to why one needs faster shutter speeds with longer lens in daylight photography.
- Set your lens to manual focus and focal length of infinity. Remember, if you have foreground per previously discussed, you need to be far enough away from these subjects such that they will still be sharp at an infinity setting.
- If the lens has image stabilization, switch this feature off.
- You may want to shoot off a few frames. Consider bracketing the time to view the impact of time on the number and shape of the stars.
- End of field instructions!
Below is my first attempt with the technique I described above. It is a simple “shoot at the sky while focus is set on infinity” shot.
The post processing was very basic, I slightly shifted the white balance and I stretched the brightness of the histogram. A dedicated astrophotographer will note slightly distended stars and magenta rings around the brightest stars. I am told that this is due to the aperture being too wide open for this lens. A more serious method is to shoot at a smaller aperture opening like f8 and to shoot multiple images and then “stack” them. One can download free software at several sites that will alight the stars during stacking,
From what I have read and seen, these advanced techniques are not that difficult and yield very impressive images; however, I will not get into these techniques in this introductory article. More information on the subject can be found at the following links:
- Another great summary article I just found is by Kevin McElharan. This article discusses detailed star shots and also star trails.
- An interesting companion article by Alister Benn “The art of available night light”
Making your shot ‘Africa’
So far, I have discussed how to take the night image and I have also noted that Africa has clear, very starry nights. For me, this could be enough, but I think Africa offers so much more. Image the sky shown earlier in this article but with a baobab foreground. Or take it one step further, image taking that long exposure and getting a fairly still animal at a water hole as your foreground. That is exactly what I planned. Below is my first attempt. It’s an elephant at the water hole with lighting provided by a nearby campfire and lights from a distant building. The lengthy exposure allowed enough illumination to capture reflections on the water, the elephant and the nearby bushes.
While this photograph isn’t as good as I hope I will get, I hope it is good enough to tease you into giving this style photography a try. I look forward to your comments and maybe some images by you once you have given these techniques a try.