Shooting star trails

In our last article we learned how to shoot all kinds of light trails, now we're going to take a deeper look at how to shoot star trails.

First of all. What are star trails?

When you look at the stars at night, they seem to be stuck, but if you stare for a couple of minutes you'll start to realize that they're moving, only very slowly. This effect is created by the earth's rotation and not by the movement of the stars themselves. Every star in the sky makes a whole turn around the pole star. This particular one is right in the axis of the earth's rotation and this causes it not to move in the sky and always head north, that is why this star has been used by travellers thousands of years ago to guide themselves in the night, yes I like science :D but we're moving away from our main topic.

What is the effect of this motion when we shoot stars at night?



If we shoot stars with a shutter speed long enought to capture this movement, the stars will create trails in the form of circles around the polar star, decorating our shot with a very interesting sky.

How do we set up our camera to achieve these results?

This will be a little more complicated than with standard light trails. First of all you will need a remote control, or any other device that allows you to use the bulb mode of your camera. Setting up the maximum 30 sec exposure configured in your camera won't be enough to capture the star's movement.
To set up bulb mode we'll need to go into manual. Se the ISO to minimum, aperture preferably to a high value and shutter speed to bulb mode. Set the focus to manual and focus on infinity.
I also recommend using a long focal length because stars will appear to move faster when the lens is zoomed in.

And this is it, you can start to experiment with different compositions and shutter speeds, keep in mind however that very long shutter speeds will create too much noise in the image, remember turning the noise reduction function of your camera to minimize this effect. If you want to have longer trails, you can create a series of relatively short exposures and then blend them together in photoshop.



It is important to be able to identify the pole star, since all the stars will turn around it, making it a strong subject of your composition. To find it look north and find a very bright star.

And last but not least, keep in mind that this kind of photography works best at clear skies without luminic contamination, so run away from big cities.

Photographs by Corica, Warner Strauss and me.

Shooting light trails

If you've read the "Mastering the basics" section you already know a lot about how to use the exposure settings creatively. In this article we're going to take a look at using long shutter speeds to get light trail pictures.

What you're going to need:

A tripod. When shooting at speeds longer than a second the use of a tripod is a must, trying to take these images handheld will result in very blurry images. You can however try to lay the camera on some stable surface but this limits your creative possibilities a lot.

A DSLR or Bridge Camera. Most point and shoot cameras don't allow for exposures longer than 1 or 2 seconds so we'll need to use a DSLR or bridge camera that lets us choose the shutter speed.

How is a ligh trail created?

The creating of light trails is very simple. When we let the shutter open for a long time any bright light that goes through the camera's field of view, will create a trail of light through the image. Used properly these trails can create very nice effects on roads and can be an interesting addition to a cityscape shot.

The first thing you have to do for getting a light trail shot is finding a place with moving lights, a typical location to start at is a driveway. Set your shutter speed to a value between 5 and 30 seconds, I recommend using the Shutter speed priority mode . Now mount your tripod and frame the shot. Once a car approaches, click the shutter button. The lights of the car will create a light trail on the image as long as the shutter is open. Review your results and try using different shutter speeds.

Using flash. Although flash is not often used in light trail shots it can create a nice effect showing the object that creates the trail and the trail itself. I recommend using rear curtain flash, in this mode the flash is shot just before closing the shutter and it makes the subjects lit by the flash appear at the end of the trail. Something like this:

Going back to the techincal aspects, i recommend using a low ISO and enabling noise reduction in your camera's menu to reduce digital noise from the long exposure.

An interesting addition to our gear if we want to shoot light trails often is a remote control. Triggering your camera from a remote has 2 advantages:

1. We won't need to touch any button on the camera, eliminating every chance of creating blur in the image.
2. It will allow us to use bulb mode, in this mode you'll be able to open the shutter with one click of the remote and closing it with a second click. This way you can't exactly control how and where the trail is created.

A very special kind of light trail are star trails, but we'll talk about that in the next article so stay tuned!