twilight

Out of the Blue: The Importance of Twilight to the Night Photographer

Twilight is one of the most beautiful times of day to shoot. It is also the perfect time to finalize compositions and setups for your eventual night photography.

The famous “magic hour” for photography extends for over two hours on either side of the setting and rising of the sun. As the sun moves closer to the horizon, it bathes our subjects in a beautiful warm and soft light considered by many to be the prime time to shoot daytime landscapes. Then, as it dips below the horizon after sunset, the exceptionally warm light illuminates the sky, and the clouds become brilliant and saturated.

As time moves on and the sun sinks even further below the horizon, soft, blue light provides an otherworldly glow. This has come to be known as “blue hour”—and it’s an amazing time to start your night photography.

Shades of Blue

Hawaii in the blue hour. Nikon D4. 15 seconds, f/11, ISO 400.

To better understand twilight and its relevance to the night photographer, let’s a take a look at the different moments that occur around sunset (these moments also occur in the opposite order around sunrise). Following are definitions of terms compiled from the U.S. Naval Observatory website:

  • Horizon—Wherever one is located on or near the earth's surface, the earth is perceived as essentially flat and, therefore, as a plane. The sky resembles one-half of a sphere or dome centered at the observer. If there are no visual obstructions, the apparent intersection of the sky with the earth's (plane) surface is the horizon, which appears as a circle centered at the observer.
  • Sunset (and sunrise)—The times when the upper edge of the disk of the sun is on the horizon. This means the ball of the sun is no longer visible, as it is just below the horizon.
  • Civil twilight—The center of the sun is 6 degrees below the horizon. This is the time of day just after the actual sunset.
  • Nautical twilight—The center of the sun is 12 degrees below the horizon.
  • Astronomical twilight—The center of the Sun is geometrically 18 degrees below the horizon.

As photographers, we are concerned with light. Specifically, usable light. We are also concerned with being in the right place at the right time! During twilight and at times of the setting and rising sun, the light changes very rapidly. We must be prepared, having scouted and found our ideal shoot positions, or a series of ideal positions, subject matter and viewpoints. This is crucial for the night photographer, because once darkness settles in, all of those things are much harder to find.

Civil Twilight

Civil Twilight color at Jekyll Island in Georgia. Canon EOS 10D. 30 seconds, f/19, ISO 100.

From the time the sun sets until approximately a half-hour later is civil twilight. This is when color starts to hit the highest clouds in the sky. We should rename it “Photographer’s Twilight” for the millions of photographs taken at this marvelous time of day. This is usually when we take what we consider “sunset” shots.

Notice the cloud positions. Are they low clouds? These will receive light for only about 15 minutes after sunset. High clouds? They will retain color for longer. While not “night photography,” this is a great time to begin scouting, planning and capturing the beautiful light of the end of the day.

Bonus:

The end of Civil Twilight is the best time to shoot cityscapes. The fading light of the sky matches the emerging city lights perfectly.

Last of civil twilight on a cityscape—Inner Harbor in Baltimore. Nikon D700. 4 second, f/8, ISO 400.

Nautical Twilight

This is the blue hour. Nautical twilight begins when civil twilight ends and lasts for roughly another half-hour to 45 minutes. The light is beginning to fade and we are transitioning into night. This is the time for finalizing locations, compositions and focus. It’s much easier to set your camera up in this dim light as opposed to starting from scratch in the dark.

Bonus:

In addition to readying yourself for the stars, this is a great time to photograph straight-up landscapes. The dim blue light at this hour serves to create haunting and peaceful scenes. Nautical twilight is also a great time to begin light painting; it’s dark enough to allow for light painting but bright enough to safely move around the scene.

Car trails and fog at nautical twilight. Nikon D4. 4 seconds, f/16, ISO 200.

Astronomical Twilight

The moment you have been waiting for! Astronomical twilight begins approximately 1 1/2 to 1 3/4 hours after sunset. It is the beginning of dark, dark. No sky light. You can now begin to get your star-point shots.

Start by testing your exposure and checking your focus. A good starting point is 30 seconds, f/2.8 or f/4, ISO 3200 or 6400. (For more info on star-point exposures, check out Lance’s blog post, “What’s the Longest Usable Shutter Speed for Astro-Landscape?”). Next, how does your white balance look? Does your foreground complement the sky? Check to ensure your long exposure noise reduction is turned off for shorter exposures.

Once astronomical twilight ends, the sky is as dark as it’s going to get. Now you’re firmly entrenched in “nighttime.” You can certainly continue with star-point and Milky Way shots, but now is a great time to get those really long star trails. Depending on the phase of the moon, exposures into the hours can be achieved after astronomical twilight.

Astronomical twilight at McDonald Lake in Glacier National Park. Nikon D4s. 30 seconds, f/2.8, ISO 6400.

Tackle the Twilights

As you can see, knowing the exact times of the different twilights is necessary for planning and executing great photographs.

There are a great many places on the web as well as various smartphone apps that will give precise twilight times for any given day of the year in almost any location worldwide. One of our favorites here at NPAN is PhotoPills. This app will help you plan not only your night shoots, but also full-moon shots, sunset and sunrise excursions, and Milky Way captures.

Take some time to become accustomed to the terms and rhythm of the twilights to greatly expand and enhance your photographic experience!

Tim Cooper is a partner and workshop leader with National Parks at Night. Learn more techniques from his book The Magic of Light Painting, available from Peachpit.

UPCOMING WORKSHOPS FROM NATIONAL PARKS AT NIGHT