Shoot for the Star

Gary Hart Photography: Sunstar, Little Colorado River, Grand Canyon

Sunstar, Little Colorado River, Grand Canyon
Sony a7RIV
Sony 12-24 f/2.8 GM
1/160 second
F/16
ISO 100

Cool as they can be, sunstars (AKA, diffraction spikes, sunbursts, or starbursts) border on gimmicky and cliché. So why do I shoot them? Because sometimes it’s the best solution when the sun intrudes on the scene you came to photograph. In other words, as much as I like dramatic clouds, vivid color, of soft light, I’d rather have a sunstar than a blank blue sky—kind of a lemonade-from-lemons approach.

Sunstars do look kind of cool, but maybe another reason they work is the universal resonance that comes with witnessing the sun kiss the horizon—I mean, who doesn’t have a comforting memory of watching from a special location as the sun begins or ends its daily journey?

Unfortunately, doing justice to these moments in a photograph is difficult: Including the sun in your frame introduces lens flare and extreme (often unmanageable) contrast, and creates an unattractive eye magnet that can overpower the rest of the scene. But while a sunstar doesn’t capture the literal experience of watching the sun’s arrival or departure, it can do a pretty good job of conveying the power of the moment.

A sunstar is created when sunlight diffracts (spreads) as it passes the intersection points of a lens diaphragm’s overlapping aperture blades. The smaller the opening, the steeper the angle between the blades, the more the light bends, and the more pronounced the sunstar spikes. The more diaphragm blades, the more spikes in the sunstar (this is a simplification of what actually happens, but you get the idea).

The good news is, despite the physical drawbacks mentioned earlier, creating a sunstar is relatively straightforward. Here’s a quick recipe:

Start with a brilliant point of light: You can create a sunstar with any bright light source—the moon, stars, or even an artificial light such as a lighthouse, or car headlights—but I’m going to talk about the brightest, most ubiquitous, and easiest light source: the sun. Rather than using the entire sun, it’s usually best (but not always—you decide what looks best) to block most of it with the horizon, a cloud, or some terrestrial feature, such as a rock or tree. And clouds and atmospheric haze will significantly limit your sunstar—sometimes I’m not even aware of clouds or haze until the sunstar I expect is faint or non-existent.
Size matters: The larger the visible portion of the sun, the bigger the sunstar, but also the more lens flare and blown highlights. Conversely, if most of the sun is blocked, you’ll get a smaller sunstar, but it will also be more precise and delicate. There’s not absolute ideal size, it’s more of a balancing act to find the right mix for your taste and situation.
The smaller your aperture, the better your sunstar: A wide-open aperture is a nearly perfect circle (not good for sunstars), but the angle between the diaphragm blades increases as the diaphragm closes down, improving the sunstar as the angles increase. For my sunstars, I generally stop down to f/16 or smaller (larger f-number).
Manage the highlights: When the sun is entering your frame, you’re invariably dealing with a sky that’s much brighter than your foreground and will need to take steps to avoid the foreground of murky shadows. If you have a foreground shape or shapes against the sky, you could turn the foreground into a silhouette. When I’m exposing for a sunstar, I watch the histogram (a benefit of mirrorless photography is the histogram in the viewfinder) and try to find a balance between the extreme highlights in and surrounding the sun and the dark shadows of the surrounding scene. I usually bracket over a 4-stop range in 2/3-stop increments, doing this as rapidly as possible to give me a good number of different exposures to choose between.
Different lenses will yield different results: Experiment with your lenses to see which one gives the most pleasing sunstar effect. As a general rule, the better the quality of the lens, the better its sunstar effect. Prime lenses tend to do a better job, but a today’s best zooms create beautiful sunstars too. And the number a sunstar spikes will increase with the number of diaphragm blades.
Remove filters: The more glass between the sun and your sensor, the more reflections and lens flare you’ll get, so remove your polarizer (which has no benefit anyway when you’re pointing at the sun) and UV filter.
Practice: You can practice sunstars any time the sun’s out. Just go outside with your camera, dial in a small aperture, and hide the sun behind whatever object is convenient (a tree, your house, etc.).

About this image

Sunstar, Little Colorado River, Grand Canyon

This scene from last month’s Grand Canyon raft trip is a perfect example of why I sometimes resort to creating a sunstar—and I nearly missed it because I wasn’t ready. On a raft trip like this, no matter how much we try to time our stops with the best light, other factors often dictate the schedule.

We were fortunate to score a campsite directly across the Colorado River from the confluence with the Little Colorado River. We set up camp in the early afternoon and motored across the river as soon as we saw the other trips clear out. So we had the Little Colorado to ourselves, but with the sun still high in the cloudless sky, I resigned myself to having to wait for the sun to disappear behind the canyon walls before breaking out the camera gear. In the meantime we had a blast navigating a natural waterslide and cooling off in pools just warm enough to be refreshing.

When the non-photographers shuttled back to camp, the photographers remained at the Little Colorado to wait for the shade. While waiting I pulled out my Sony a7RIV put a 6-stop neutral density filter on my Sony 24-105 G, and wandered up and down the river looking for whitewater to play with. This was mostly just an exercise to kill time and familiarize myself with compositions for later, but was having fun I kind of lost track of time.

Not having really thought about the path the sun would take, and whether a sunstar would be an option, I looked up and saw that the sun was about to disappear behind a peak directly downstream and suddenly recognized a perfect sunstar opportunity. But my camera bag, with the Sony 12-24 GM lens I needed to get everything in (and also with the best sunstar), was about 200 yards downstream.

Not sure I had enough time, I sprinted as fast as my flip-flops would carry me, grabbed my bag (which was already in full shade), and sprinted back upstream toward the retreating sunlight. The sunstar happens right at the intersection of sunlight and shadow, but when raced into the sunlight I continued a little farther to give myself enough time before the sun set.

I really couldn’t afford to be picky about a composition but was lucky to find something with a foreground (rock) and middle ground (the blue of the Little Colorado) to go with my background (red-rock peak and sunstar). With the sunstar already in full swing in my viewfinder, I quickly (frantically) framed up a composition (no time for my customary obsessive tweaks, reviews, and refinements), dialed to f/16, metered (have I mentioned lately how much I love having a histogram in my viewfinder?), and clicked.

I only got four decent sunstar frames before the sun was gone. I had no idea if I had anything usable because I don’t usually perform too well when I rush, but was pretty happy to find something that works.