Blue Hour Photography

Gary Hart Photography: Blue Hour, Diamond Beach, Iceland

Blue Hour, Diamond Beach, Iceland
Sony a7RIV
Sony 100-400 GM
15 seconds
F/20
ISO 50

If you’re fortunate enough to be outside after the sunset color has subsided, but before the world is enveloped in total darkness, you may find yourself basking in the rarified hues of the “blue hour*.” It’s called the blue hour because, wait for it…, the landscape is indeed bathed in blue. (And also because it just rolls off the tongue better than “the blue 20-minutes,” which would actually be more accurate.)

The greatest joy I get from photography is the connection it gives me to the natural world. Whether it’s lightning, a celestial event, a geological feature, some technical aspect of photography, the qualities of light, or whatever, whenever possible, in my blog posts I try to share something of the science behind my subject or its capture. The goal of this sharing isn’t entirely altruistic—it’s also a great excuse to dig deep into things that absolutely fascinate me. And as it turns out, the science behind the blue hour is especially fascinating.

The blue hour actually last less than one hour, with its duration decreasing with latitude because come and go faster the lower the latitude because the sun ascends and descends at a steeper angle. A lower latitude also speeds sunrise, sunset, and the other stages of twilight for the same reason. This means that in Hawaii, if I’m on location 30-minutes before sunrise, I can probably catch the entire show, whereas in Iceland, even if I’m there 90-minutes before sunrise (brrrr), I might miss something. In the mid-latitudes, 20-minutes is a reasonable rule-of-thumb blue hour duration to rely on.

The cool thing about blue hour color is that, unlike daylight blue sky and sunrise/sunset color, it’s not a function of scattered sunlight. (Read my Sunset Color Photo Tips article for more on this.) Instead, until the sun drops about 8 degrees below the horizon, its blue wavelengths are absorbed by ozone in the upper atmosphere. Though this absorption (Chappuis absorption, if you must know) happens when the sun is above the horizon too, its effects are completely overpowered by direct sunlight. But as direct and scattered sunlight fades with the sinking sun, about the time the sun is about 4 degrees below the horizon, the blue ozone sky enjoys its 20-minutes of fame. (In other words, the blue hour reigns when the sun is between 4 and 8 degrees below the horizon.) Because the cones in our eyes require a certain amount of light to register color, this twilight blue is fairly subtle, but still noticeable, to human vision. A camera, on the other hand, with its ability to increase its light sensitivity (ISO) and accumulate light over time (shutter speed), has no problem capturing the dominant blue cast.

Nature photographers love the blue hour, both for the otherworldly hues that aren’t possible any other time of day, and for the exquisitely soft, shadowless light that’s a joy to photograph. The key for getting the most out of blue hour photography is understanding that the camera sees the world differently than you. Some of the best blue hour photography happens after the color is nearly gone from our eyes, making it easy to pack up and go home. But as I said earlier, the camera can see color too faint for our eyes to register. The color camera might pick up can range from a purplish mix of the longest waves of sunlight and the beginning of the blue hour light, to the absolute deep-blue that soon fades to night.

The blue hour is also absolutely the best time to photograph the moon, which is why you see so many moon images in the Blue Hour gallery below. While fitting the dynamic range of a daylight-bright moon above virtually dark landscape is tricky, it’s definitely worth trying because the darker the sky, the more dramatic the moon will appear in your image. (Check out my articles on moon photography in the Photo Tips menu above.)

One of my favorite blue hour subjects is the ocean, because the low light means long exposures that turn the surf into a gauzy haze. In Iceland last January for a workshop, I was photographing the surf washing up onto Diamond Beach in the fading twilight. As the blue hour descended, I was drawn the way the distant snow-covered peaks (that’s Vestrahorn on the right) seemed to glow in the bluish twilight. Looking for something to put in the foreground, my eyes landed on a pair of (relatively) large icebergs just offshore and I positioned myself to align them with mountains.

Though I’d spent most of the evening shooting with my widest lenses, for this shot I switched to my Sony 100-400 GM to compress the distance between the mountains and nearby ice. Before dialing in my exposure settings, I studied the icebergs to make sure they were stationary enough to not blur in a long exposure, and decided it would be work if I could expose between waves. It took a few tries, but I finally managed this 15-second exposure.

* The blue hour of course happens in reverse before sunrise (from dark to light); for simplicity sake, I’ll just describe the evening half of the phenomenon.

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Blue Hour

Click an image for a closer look, and to view a slide show.

You Can Only Get So Wet

Gary Hart Photography: Vestrahorn Reflection, Stokksnes Beach, Iceland

Vestrahorn Reflection, Stokksnes Black Sand Beach, Iceland
Sony a7RIV
Sony 16-35 f/2.8 GM
5 seconds
F/11
ISO 100

Vestrahorn, on Iceland’s southeast coast, is one impressive chunk of rock. Turns out it only reaches 1500 feet above sea level, but the way it juts so abruptly from the volcanic sand of Stokksnes Peninsula, Vestrahorn creates an imposing presence that rivals El Capitan in Yosemite.

This Vestrahorn shoot came toward the end of the 10-day Iceland workshop Don Smith and I led in January of 2020. Arriving late afternoon (which comes pretty early in Iceland in January), the group instantly scattered across the vast, flat plain offered with a variety of foreground options that included black-sand dunes, iced-over puddles, and a vast black sand beach. I made my way down to the beach and, being a sucker for reflections, was quickly drawn to glassy sand behind each retreating wave.

The beach here is so flat that the surf isn’t dangerous (at least it wasn’t on this day), but this was January in Iceland, so I didn’t really want to get wet. On the other hand, getting the reflection I wanted required being well into the wet part of the sand behind a retreating wave, and each reflection only lasted a few seconds before the water soaked into the sand. Emboldened by waterproof boots that reached about a foot up my calf, I wandered out to where it appeared the waves only reached a depth of 2 or 3 inches, not quite far enough to ensure a full reflection with each receding wave, but not too bad.

I really had a blast working this scene, playing with different compositions as the clouds and light above the mountain changed, and varying my timing to capture each wave in different stages of motion, from the frothy white churn at the wave’s front, followed by the floating foam shapes trailing it, and finally the reflective sheen punctuating each retreat. I also tried a variety of shutter speeds, freezing or applying a variety of blur effects to the moving water. When I get into this zone, I lose all sense of time a surroundings…

So imagine my surprise to feel freezing water soaking my feet. I looked down to see that my legs from the knees down had disappeared, and the beach I’d been standing on now more closely resembled a lake. With the tide clearly coming in (hmmm, perhaps that’s why the reflections seemed to be getting better…), my first inclination was to retreat. But the photography was definitely better in the deeper water, safety wasn’t a concern, and I suddenly remembered my running mantra: You can only get so wet, and once you get that wet, you’re not going to get any wetter. If this mindset could get me through several extremely miserable marathons, it could certainly get me through this. I hadn’t planned to soak my feet in the chilly surf, but now that the damage was done, I couldn’t really make it any worse. So I ended up staying out there, joyfully surrounded by reflections, for another 30 minutes.

One of the things I’ve learned over many years of photographing in extreme conditions is the value of backups. Not just backup photo gear, though I do think it’s foolish to take any photo trip with just one body (I’d already had to spend two days on this trip using my backup body, waiting for my primary body to dry after a unplanned dip in the surf), but also backup clothes.

So loading into the van (not sure what to call our vehicle: it was either a huge van or a little bus) at the beginning of each day, I always made sure to leave out a change of shoes and socks. Though my marinating feet were okay while I was shooting, as soon as I finished and started heading back to the van/bus (ban? vus?), they suddenly became wet, frozen stumps. I never imagined something as simple as a dry pair of socks could bring so much joy.

Read more about reflections


Surf’s Up

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Blue Hour

Gary Hart Photography: Blue Hour, Vestrahorn, Iceland

Blue Hour, Vestrahorn, Iceland
Sony a7RIV
Sony 12-24 G
8 seconds
F/16
ISO 50

“Many of us would probably be better fishermen if we did not spend so much time watching and waiting for the world to become perfect.” 
― Norman Maclean, A River Runs Through It

I haven’t fished in years (decades), but of course Norman Maclean’s words really aren’t about fishing anyway. Nevertheless, I’m reminded of this quote every time I find myself frozen by minutia, mired in the moment by small distractions that matter very little, or looking for excuses not to take pictures.

There are a lot of reasons not to take a picture—tell me if any of these sound familiar: “The light was better yesterday”; “The light will be better tomorrow”; “It’s too cold”; “It’s too hot”; “It’s too wet”; “I’m hungry”; “there’s dust on my sensor”; “This lens is soft,” and on, and on….

This Vestrahorn shoot came toward the end of the 10-day Iceland workshop Don Smith and I led in January of this year (was that really only 4 months ago?!). As the sun disappeared on this chilly winter evening, there were a lot of reasons not to stay out photographing: it was cold, I was wet, the clouds, it was getting dark, and there was a 90-minute drive separating us from dinner. It had been a nice shoot, but I was a little disappointed that the sky that had looked quite promising all afternoon, never really delivered the color I’d been waiting for. But before heading back to the van, I wandered up the beach a bit and found this rocky section that was different from the waves, and the reflections left in their wake, I’d been concentrating on all afternoon. As I reconsidered whether to call it a day, I came upon a lone shell embedded in the sand. With the light fading fast, I quickly dropped my tripod as low as it would go and set up with my Sony 12-24 G lens on my Sony a7RIV, and went to work.

Before I knew it, the “blue hour,” that magnificent transition from day to night (and back) that always looks better on an image than it does to the eye, had taken over. If you’ve ever stayed out to photograph after your eyes tell you it’s time to go in (or started shooting a little early while waiting for sunrise), you know what I’m talking about. What we humans perceive as darkness is really just our eyes’ relatively limited ability to gather light at any given instant. But a camera’s sensor (or a rectangle of unexposed film) can patiently accumulate all the light striking it for whatever duration we prescribe, thereby stretching its “instant” of perception indefinitely. Advantage camera.

On a clear night, you can actually watch the Earth’s shadow descend and engulf the landscape in deepening blue light. And unlike daylight (and moonlight) photography, when a discrete light source casts high-contrast shadows that test a camera’s dynamic range, and starlight photography, when the light is so faint that extremely long exposures are required to register any foreground detail at all, in the pre-sunrise/post-sunset gloaming, a camera can still “see” these diminishing vestiges of daylight. Given enough exposure, the image’s world is rendered blue, and because the entire sky is the light source, this blue hour light is spread so evenly that most shadows disappear.

When I can, I’ll stay out at least long enough for the first stars to pop out. On this evening, because I didn’t want the rest of the group to have to wait for me, I wrapped up before the stars appeared, but still stay out long enough to capture this 8-second exposure—my very last image of the evening. The perfection I’d been watching and waiting for never made it to my eyes, but fortunately my camera revealed that it was there all along.

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Blue Hour

Click an image for a closer look, and to view a slide show.
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