Whenever I photograph at a popular location outdoors, I always see a mass exodus of photographers as soon as the sun goes down. For many years, I was part of this exodus, as I believed the best light was gone as soon as the sun set. This was before I discovered the magic of the twilight hour. Now, I see the sunset not as the end of my photo shoot, but the beginning.
There are three stages of twilight – civil twilight, nautical twilight, and astronomical twilight. Each of these stages lasts about 30 minutes, though it can be longer or shorter depending on where you are on the planet and what time of year it is. You can determine the exact times each of these twilight stages occurs on many websites, including the Astronomy section of WeatherUnderground.com. You can also find this information on apps like PhotoPills or The Photographer’s Ephemeris.
The first stage of twilight after sunset and the last stage before sunrise is known as civil twilight. It occurs during the time the sun is between 0 to 6 degrees below the horizon. During this time, you can often get vibrant colors in the sky, since a lot of light from the sun is scattered and refracted by the atmosphere. The clouds may have some of the bright orange or pink glow that you would see at sunrise or sunset. You can also capture images of the Earth’s shadow, which is the shadow that the Earth casts on its own atmosphere. This shadow will usually appear with a bright pink band of sky above it, known as the Belt of Venus or the anti-twilight arch.
Civil twilight is a good time to capture images of the moon and some of the brightest stars and planets. The moon will be visible throughout this time, while some of the stars and planets will be visible towards the end of civil twilight in the evening (or the beginning of it in the morning).
The period when the stars and planets are just visible is often referred to as the “blue hour.” During this time, blue wavelengths of light from the sun are more easily refracted by the atmosphere back onto the land, making the scene appear bluer than normal. This effect is most pronounced during the time the sun is about 4 to 6 degrees below the horizon, though it is noticeable before and after this time.
You can capture some interesting images during the blue hour if you are photographing something that is already blue, like the ocean. It can deepen the blues even more, giving a somewhat surreal effect to the photo. This may not be as desirable if you are photographing objects that aren’t blue, as it can give the appearance of a color cast across the image. In this scenario, you can increase the white balance temperature until you remove the color cast.
During civil twilight, it will usually be light enough out to get good exposures using your camera’s exposure meter. However, you should check the histogram after you take your shots. Make sure the data extends to the right side of the histogram, without blowing out any highlights.
Although civil twilight is a great time to capture photos, the magic of twilight does not end here. Nautical twilight and astronomical twilight also offer some incredible photographic opportunities. I will discuss each of these in my upcoming articles.
Continued at: The Magic of Twilight: Part II