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Time Exposures and the Milky Way

Grass Tree and Milky WayI've learnt to love the effects of slowing down time in a photograph.
If I am under a night sky and I just look at the stars there is lots to see, but a time exposure allows the weakest of stars, even those your unaided eyes cannot see, to be recorded by my camera, but this is not as simple as taking a quick snap.
The important thing to start with is to understand that the prolonged recording of an image creates the effect one is searching for, but it also brings many problems.
The only way to do a time exposure is to leave the shutter open for a set period of time, usually done with a built in timer or by using the Bulb setting and manually or externally controlling the shutter opening time. Most DSLR cameras allow for a maximum open shutter time of thirty seconds, and this is more than enough for Milky Way shots, but often not enough for other types of time exposure. Today I'll just talk about photographing the Milky Way.
I like to use a fast lens, that is, one that can open a large aperture, at least f4.0 but preferably say f2.8, but it also needs to be a wide angle lens, preferably around 16mm. I often use a Canon 16-35mm F4.0 and a Samyang 14mm f2.8, both with good success.
Because I will be recording for several seconds, it is imperative that the camera does not move while the shutter is open, so I like to use a sturdy tripod, although I have just held the camera down firmly on a rock, or even on the roof of a car.
In order to increase the sensitivity of the camera sensor I set the ISO. Because I use a Canon 6D, I can set the ISO at 6500 or even higher, but other cameras may need to be set lower. You may be able to find out about your camera online, or you may just have to experiment.
The final decision you must make is to select the shutter speed. I like to select around 20 seconds and let the camera do the timing.
So, in summary, use a steady tripod, a fast wide angle lens and select a high ISO. Point your camera and try out 20 seconds. Just experiment from there until you get a picture you are happy with.
The image here is of an Australian Grass Tree with the Milky Way behind.


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