The Twilight Zone: Shooting After the Sun Goes Down
I often see people taking pictures at sunset. After all, I'm often right there with them, doing the same thing. As the evening progresses though, most everyone else leaves by the time the sun goes down. But with plenty of great images to be made as the light continues to fade, they're missing out on perhaps the best part. Welcome to the "twilight zone."
For argument sake, let's consider twilight to be the time from when the sun itself has dipped below the horizon, until it is so dark the sky has become a uniform inky black, if you discount any light produced by the moon, stars, artificial lights and the like. Technically, this period ends when the sun has dipped to a full eighteen degrees below the horizon. Where sunset photography ends, twilight photography begins. The "twilight zone" generally lasts for a good hour after sunset.
The first thing to know about twilight photography is that by the time twilight is over, it's dark. My contention that this is the first thing to know is based on the fact that, if you wait until twilight is over, it's too late and you can't see to find your way back to where you need to be for the night. Make sure you have a flashlight. In fact, make sure you have two, just in case. One way that sunrise photography differs from sunset is that, if your flashlight dies you can always sit down and wait a while till it gets light. If you stay until it gets dark at sunset and your flashlight dies, you're going to be waiting all night for it to get light again. Even if you got some great shots, this situation would surely put a damper on your evening. Be safe, and plan ahead.
Temperatures can begin to dip rapidly once the sun goes down too, so be sure to dress accordingly. If you have to hike to get to your photographic destination, it can be easy to forget that once you get there you will be doing at least a bit of standing around, waiting for the magic light. You may have been plenty warm while on the move, but you can chill rapidly once you get there and the sun starts to set. Dress in layers, and be prepared, or else your twilight adventure will turn rather miserable, rather quickly.
Having gotten these caveats out of the way, let's consider what there is to photograph at twilight. If most everyone leaves when the sun goes down, maybe they know something you don't. But on the contrary, even though it's too dim to see much yourself, your camera has no such difficulty. It just needs a bit more time to get a decent exposure that it does during the day. It's not that it's getting tired or anything, it's just that it takes longer for sufficient light to reach your camera's sensor when it's that dim. But if you have a sturdy tripod and you are willing to wait, you can get any exposure you are after.
And patience can be rewarding indeed. I enjoy capturing images that show things in ways most people generally don't see, so they look at them as if anew. Popular photographic locations abound if you only but look for them, but the trick is to get shots that not everyone else does. Twilight is one great way to approach this challenge.
Most of the color at twilight comes either from the fading light of sunset, or from the sky low to the horizon directly opposite the setting sun. As such, you'll need to do a bit of planning to position yourself optimally relative to your subject to make the most of what you are presenting with. The sky directly above you will be near black, with colors ranging from dark to medium blue below that, depending on exposure time, and finally ending with a band of orange near the horizon if the sun hasn't been gone so long that even this has faded. But all of these colors can also be found picked up by water or other reflective surfaces. Again, a bit of thought and planning are necessary to use this color to your advantage.
With light levels low, it is common for objects positioned against the sky or something reflecting the color of the sky to render as silhouettes. One silhouette stacked on top of another will become nothing more than a black blob in your final image. Look for objects that will still be recognizable as silhouettes, and strive for separation between those key objects and everything else. Changing your tripod position will often do the trick. Don't forget that you can raise or lower your tripod as well. A change to your shooting height can also help by allowing you to place your subject where the sky color is at its maximum. It is rare indeed that your best twilight shot will be from eye level.
Back in the days when film ruled the world of photography, twilight exposure was tricky indeed. You could do your best to meter and then compensate for reciprocity failure if needed, but in the end you really couldn't check if you had done things right until you got back home and had your film developed. When you did, if didn't get what you were after, you could only try again by going back to that location some other time. Even being able to tell what you were taking a picture of wasn't a sure thing since it was hard to see. I once shot an entire roll of film in the North Cascades at twilight only to find out later there was a trail marker sign plainly visible in every shot. When I was on location, that sign was lost in darkness as far as my eyes were concerned.
Luckily, digital has changed all that. The histogram and LCD display have made even low light exposures very doable. What your eyes can't clearly see, your camera can, if given the time to properly expose it. These days, there's no excuse for photographers not being willing to experiment a bit to see what they can push themselves and their equipment to do.
I encourage you to explore the "twilight zone."