Photography tricks: How to create star effects from light sources
Stars, a lamp or the sun: By closing the aperture on your camera, a star effect is created with any light source. This effect has many names, from sun stars, starbursts, sun flares to star effects.
To create a star effect on streetlights, spotlights or even the sun (should we get to see it ever again), the aperture needs to be minimal. Turn the mode dial on your camera to A or M (aperture preselection or manual) and then select a small (closed) aperture. To be clear: f/4 is a large, open aperture, f/22 a small aperture.
Suitable light sources
Small and strong light sources are more likely to produce a star effect than large and weak ones. A candle flame, for example, is unsuitable for close-up photography. From a certain distance, however, it's possible to create star effects with candles.
The effect becomes particularly visible when part of the light source is hidden, especially with strong light sources such as the sun. The clearest rays of light are produced when the sun shines between branches or is partially covered by the horizon. In other words, at sunrise and sunset. There's a simple trick that works when there's no obstacle: Position the sun to the edge of the picture, making sure only part of it shines into the picture.
In the case of headlamps, your best bet is to point them directly at the camera.
It depends on the lens
The number and length of the rays or points of your star depend on how your aperture is designed. Let's take a look at this lens, for example:
The lens has seven blades, the aperture forms a heptagon. It produces 14-point stars. Why? An odd number of blades produces twice as many rays as there are blades.
Some lenses have rounded blades, resulting in an almost circular aperture. This produces a nice bokeh effect, but no nice star effect. In other words: Not every lens is suitable to create a star effect. You’ll have to give it a go and find out what your lens can do.
Beware of stains
Closed-aperture photos make stains on the lens and sensor easily visible. If you're like me and usually take pictures with an open or half-open aperture, you won't notice if the sensor is dirty. To avoid unpleasant surprises, make sure the lens of your camera is clean before you start your photography project.
My interest in IT and writing landed me in tech journalism early on (2000). I want to know how we can use technology without being used. Outside of the office, I’m a keen musician who makes up for lacking talent with excessive enthusiasm.