Three tips, better shot: Starbursts at Hoover Dam

You know those photos you see all over the Internet – the ones that turn seemingly ordinary things like streetlights into a starry wonderland? You know, sort of like the streetlights around Hoover Dam in the featured photo of this post?

Sure, you can buy a filter to add star points to your photos, but there’s also an easy way to achieve this effect in the camera without any extra tools.

It’s a quick an easy way to make what would have been an ordinary photo into something a little more exciting.

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Tip #1: The narrower the aperture, the more pointed the star will be

Hoover Dam, without the starbursts. This was shot at 1/4 sec, f/1.4 and ISO 400.
Hoover Dam, without the starbursts. This was shot at 1/4 sec, f/1.4 and ISO 400.

Take a look this photo above – it’s the same scene and framing as the featured photo, but it looks very different. That’s because instead of being shot at f/14, which is what the featured photo at the top of the post was shot at, this one was shot at f/1.4. Instead of starbursts, the lights merely become blobs.

There are two considerations to keep in mind to create these starbursts from ordinary points of light – lens and aperture.

The smaller the aperture, the more defined points you’ll see. The choice of lens will determine how many “points” your star will have – and it’s not just a matter of a more expensive lens. Every lens has a different number of aperture blades and some lenses have curved blades while others have straight ones. Some older lenses will have more blades and some won’t – it’s one of those obscure things to look for on a lens spec sheet if you’re interested in this.

In general, an even number of blades will give you an equal number of points (6 blades equals 6 star points) while an odd number will give you double (9 blades means 18 points).

Tip #2: Go high, but not too high

If you narrow your aperture too much (say, f/32 or near that) you may start to see your image get softer due to diffraction – the camera’s sensor can’t resolve detail at that sort of setting. There’s a whole physics explanation involving the bending of light as it hits the sensor that causes this, but take my word for it – if you go too small, you’ll start to negatively affect the sharpness of your image. It’s also one of those things that’s hard to display in a compressed JPEG file on the Web, where everything seems to look a tad softer than the file actually is.

So the key here – pick a small enough aperture to get your starbursts, but not so small you get a softer image. Larger sensors have a higher tolerance than smaller sensors.

Tip #3: Know the weaknesses of your lens

Hoover Dam shot at 16mm. This was a 196 second exposure at f/20, ISO 400. Note how the starbursts get even more pronounced at these settings.
Hoover Dam shot at 16mm. This was a 196 second exposure at f/20, ISO 400. Note how the starbursts get even more pronounced at these settings.

Some lenses will be great for this task. Some will be lousy. I was surprised that something that’s considered a portrait lens (the Canon EF 85mm f/1.2L II) was actually able to do these star-points in a situation that was probably better suited for a wide-angle landscape lens. This photo above from the Year in Photos post was shot with a wide angle lens and created some crazy looking stars, of a very different style than the 85mm.

At f/1.4, the lens shows some chromatic abberation that isn't present at f/14, so stopping down in general isn't a bad idea.
At f/1.4, the lens shows some chromatic abberation that isn’t present at f/14, so stopping down in general isn’t a bad idea.

Along with that, you have to know the strengths and weaknesses of your lens. If you look at the two 100 percent views of the photos from this post, you’ll see that at f/1.4, the 85mm exhibits what’s known as purple fringing, or a purple halo around edges of contrast. At f/14, that’s gone. This is but one thing to watch out for when you push a lens to its limits, but every lens will show some differences at the extremes of their apertures.

Good luck with your own attempts at starbursts – and remember to use a tripod!

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