As Promised here is some information to help people with their lens choices for photographing the night sky.
I dont believe there is any real answer to “what lens should I use for night sky photography”. Personally I think its up to the artistic vision of the photographer to choose what suits best.
In this post I will run through a few examples, to show how different lenses can be used and how they can change a scene dramatically.
If you havn’t already it would be really benificial to go and read my first post on basic night sky photography before you continue reading.
Lets start with a few comparison shots. The above picture is of the same Aurora at almost exactly the same time taken near the 90 mile beach Victoria, Australia. The top pic is taken with a canon 1200D and 18-55 kit lens at 18mm and the bottom a Canon 6d and samyang 14mm 2.8.
I took these two pictures to prove that you can get a great picture of an Aurora with a simple kit set up, (actually the cheapest most basic canon dslr I could find).
As you can see there is quite a difference between the two. The kit lens at 18mm (approx 28mm true focal length, remember cropp factor?) is showing a narrow field of view. Where as the 14mm and the 6d with its full frame sensor is showing an extremely wide view.
Here is a couple more.
The picture on the left is taken with a canon 6d and 28mm lens. The picture on the right is taken with a Canon 6d and 14mm lens.
As you can see these two combinations give very different results in a similar situation, actually the focal length is almost exactly the same as the previous example. The 28mm lens shows just a portion of the milkyway and compresses the scene making the milkyway seem closer and more dominant. The 14mm lens on the other hand allows you to see more of the milkyway rising above the tree and it looks further away.
You can see in these picturess the wide angle can show alot of the night sky, lets have a look at a fisheye lens.
Canon 6d, sigma 15mm fisheye f2.8, 30sec, 6400iso
The fisheye captures an incredible amount of sky and foreground, its slightly shorter than 14mm but being a fish captures a little more, the only downfall is a lot of curvature/distortion with its fisheye view, although well hidden in this example. I found the fisheye limited in the amount of situations I could use it because of the amount of curvature it produces.
Lets see something different!
Canon 1DMKIV 130mm, f4, 25 sec, 800iso
This picture is from a lookout in my home town Stratford. I used a canon 70-200 lens for this image at a focal length of 130mm (170mm true focal length when cropp factor is taken into account). It gives a totally different look again compressing the whole scene, bringing the trees and distant mountains in closer and giving large star trails as we broke the 600 rule by alot, still a nice night sky picture and exactly what I was after.
Lets break the 600 rule by a lot with a wide angle lens.
Canon 1D MKIV, 17mm, f5.6, 217sec 200iso
The above picture is my first ever Aurora I unknowingly captured while out shooting long exposures and light painting under a full moon (look on the right). It was taken at 17mm (21mm true focal length) at f5.6 200iso for 217sec.
At 21mm true focal length and such a long exposure. It’s given a wide scene with streaking clouds, longish star trails, soft water, movement in the orange fence and gave me enough time to light paint some of the scene, including walking in front of the camera during exposure. Obviously I also got the added bonus of the Aurora, who said you need a fast lens and short exposure to shoot Aurora!
As this is aimed at someone new to night photography I’ve left out longer focal length lenses such as 400mm. I’ve also left out any recommendations on particular lenses as I wanted to illustrate you can use almost any lens/camera and get interesting images. I feel a lot are put off even getting out to take night sky images if they dont have the “right” equipment.
I suggest go out and see what you can do with what you already own, practice with the 600/500 rule, get technique right and then break it with longer exposures, you may be suprised at what your current gear is capable of.
But for those wanting to step up I will be writing another blog to accompany this one with more specific information on what to look for in a lens and some popular lens choices.
Enjoy your photography. Get outside, explore your back yard.