Photography Tips and Tricks
What is Starburst effect?
How to create or avoid having starburst effect in your images?
Take a look at the Budapest’s Chain Bridge, the featured image of this post (here above).
The effect you see around the light sources (e.g. in the foreground) is called Starburst effect. In this article I will briefly discuss how to create or avoid having starburst effect in your images.
The phenomenon itself is associated with the shape and size of the aperture. Hence, the lens you are using and the aperture of your choice have enormous impact on the creation and shape of the Starburst effect. Aperture is formed by a few blades that move over each other and by doing so they can create a smaller or wider aperture. Based on the form of these blades the aperture can have polygonal or perfect circle shapes.
Figure 2. In this figure you see a polygonal aperture. The blades of diaphragm can move over each other to make the aperture smaller or wider.
When the aperture has a perfect circle shape there will be no starburst effect, instead discs of light -not necessarily visible- will be formed that cause the image to look less sharp. When the shape of the aperture is polygonal and you have light sources in the scene then you will see the starburst effect. The smaller the aperture, the more pronounced the starburst effect will be. Hence, the recipe for a pronounced starburst effect consist of a small polygonal shape aperture, and having light sources in the scene. The effect can be created at both day and night times. The shape of the starburst may differ from one lens to another one. If your lens has a circle shape aperture, there are filters you can use (to buy or self made) in order to create the effect.
Figure 3. The smaller the aperture the more pronounced the starburst effect is.
How to avoid having starburst effect:
Starburst is not an effect that everyone will fall in love with. In fact some may dislike it and wish to avoid having it in their images. If this is the case for you, there are several strategies you can implement in order to avoid having starburst effect in your images;
1- Use a lens with a circle shape aperture. Although this might be an ideal solution, but most lenses have diagonal shape aperture. Hence, this might not be the most practical solution.
2- Use a wide aperture. As you have seen in Figure 2 , the wider the aperture the less visible the starburst effect will be. Hence, you need to practice with your lens(s) and find out at which aperture the effect is minimum. This is also not an approach that you can use at all time. For instance, because you want to create an overall sharp image or because you wish to extend the exposure time by using a small aperture.
3- If possible change your composition or the timing of shooting. Changing the composition (in particular changing the angle of view) may avoid having the light source(s) in the scene. Also most light sources are time dependent (sun; day time, city lights; present at darker hours). Hence, changing the time of shooting could resolve the issue completely.
4- If non of the above measures are not doable, you can make two images, one with a wide aperture just to prevent the starburst effect, and the other one with the aperture of your choice. Later on, you can combine these two images in photoshop in order to create an image without (or less visible) starburst effect.
I hope this was helpful. If you have any comment or question or if you have another solution for creating or avoiding the starburst effect, please do not hesitate to share it here.