When shooting into the sun or other light sources, you may notice that some of your images have a unique quality to the light – this is known as a “starburst” effect. This can create a very strong focal point and add an entirely new dimension of interest to your image.
This effect is not just limited to the sun – any light source has the potential of creating a starburst such as street lamps, headlights, or even reflected light. This technique is especially useful at night, as the many lights that decorate an urban scene can become a starburst, as seen below.
What Causes a Starburst Effect?
When you have a light source that is significantly brighter than the surrounding environment (such as the sun during the day, or almost any kind of light at night), the starburst effect becomes more apparent – but there's more to it than that.
To make a long explanation short, a smaller aperture will exaggerate the rays of light you see when compared to a wider aperture. When your aperture becomes small, the blades will create stronger angles which produce this effect as the light hits your sensor. When you shoot wide open, your aperture will be more round, giving you a softer light source.
Let's look at the difference between a wide aperture and small aperture:
The photo above, shot at f/16 (small aperture), shows a great example of a starburst effect. The rays are strong and prominent which create a dramatic focal point.
In contrast, the photo above was shot at f/1.8 (wide aperture) with the focus on the foreground wheat grass. Notice how soft the sun is when compared to the previous image.
Since you're using a smaller aperture to get that starburst, most of your image should be in good focus. However, for the sharpest image possible, try to lock the focus on your main subject so that your focal point is tack sharp. You can find a more detailed explanation on how to focus properly by clicking here.
Starbursts at Night
The starburst effect isn't limited to the sun – any light source can produce these rays, even when you're shooting at night. As seen in the image of the bridge above, you can comprise an entire image of small starbursts which can add so much interest to an otherwise dull photograph. However, make sure to use long exposure methods when shooting at night – otherwise, you may end up with a very blurry and/or underexposed photograph.
TIP: When using a tripod, turn any “image stabilization” or “vibration reduction” off – this is only useful when your camera is handheld and can actually do more bad than good if you're using a tripod.
Remember, any light source can produce a starburst – even reflected light. This technique is used widely in macro photography where dew drops on flowers reflect the sun, thus producing their own mini-starbursts throughout the image.
In the image above, you can see that the reflected starburst light is a huge focal point of the photo, which turned a common macro subject into a unique image.
Think Twice About Shooting at f/32
Reading all these great things about starbursts may persuade you to stop down beyond f/16 to obtain a very dramatic starburst. If you're concerned with sharpness, resolution, and overall image quality…this may not be the best idea.
You may have read previously that using a small aperture can actually be a bad thing if you push it too far. Generally speaking, lenses are their sharpest in the f/8 – f/11 range – known as the “sweet spot”. When you adjust your aperture wider or smaller than this, the overall quality can be reduced – this is more apparent on the smaller side (f/16 +) than it is on the wider side.
How far you should go is entirely up to you and what you consider a good photograph. Personally, I wouldn't go beyond f/16 unless the situation absolutely calls for it. There are plenty of beautiful images taken beyond this point – for example, the water drop image above was taken at f/20. You can see that the photo has a slightly reduced level of clarity to it, but the fantastic starburst captured outweighs this minor drawback. Experiment with different apertures to see what you consider an acceptable range.