Photography Tips and Tricks
How to create light trails
The lines of light you see in the above image are called light trails. These are light trails of a moving tram without the tram itself to be seen.
Light trails are created when you have vehicles with head and/or tail lights moving through the scene and you are using a slow shutter speed. The phenomenon is dependent on the shutter speed and the presence of a moving light source(s) like cars, trams, trains, bicycles etc. How slow the shutter speed should be, depends on the speed and the distance of the subject (that carries a light source).
- when the subject moves very fast -like a car on a highway in Germany- with a shutter speed of even 1 second you might be able to catch the light trails. While when your moving subject is a bicycle or a car driving with city limits, then the shutter speed should be slower.
- For a subject far away from the camera you need to have a slower shutter speed comparing to a subject that moves right in front of the camera.
In general a shutter speed of 5-30 seconds should be enough to capture the light trails. In case you want to avoid having light trails, then you need to make the shutter speed faster. This can be achieved by using a wider aperture, increasing the ISO or shooting at an earlier time point of the day when there is enough ambient light available.
Image 1. A combination of tail lights and a motion blur of the moving subject
Now look at image 1, of a moving train (shutter speed 1/3 of a second).
In this case, you see the train itself in motion blur and the light trails of tail lights. This is because the shutter speed (1/3 of a second) is relatively fast. Hence, if you prefer to have the light trails as well as a motion blur of the subject that carries the light source, then you need to have a relatively faster shutter speed. This is also a popular approach when photographing cities with traffic at night. I am sure you have seen many images of London’s red buses at night that are created in this way. By reducing the shutter speed you will be able to capture only the light trails. Hence, remember that there is no hard rule to say that the shutter speed should be this for creating light trails with or without the moving subject in motion blur. It is always a matter of experimenting and also how you like the final image to look like.
Also note that reducing the aperture size (higher f/number) to make the shutter speed slower, will create starburst effect around the stationary city lights (e.g. in Image 2, upper right corner). In a previous blog I have explained how to create or avoid starburst effect. Furthermore, when shooting with a slow shutter speed it is wise to use a cable release in order to prevent camera shake.
Image 2. Light trail effect can be emphasised by photo stacking.
Image 2, is a scene from Minsk city (Belarus) on the new year’s eve. Although I have been using a slow shutter speed (20 seconds), due to the lack of traffic, it was not possible to create this amount of light trails on the streets in a single shot. In such a situation, I would use photo stacking. Basically I will make a few images in a row and then I will stack them on the top of each other in photoshop. If you are unfamiliar with photo stacking read my next blog on how to do photo stacking in photoshop.
I hope this was helpful, should you have any comment or question please do not hesitate to send me a message.