Just because the sun has gone down doesn’t mean its time to put the camera away
Whether I’m out in nature or wandering a city, I am just as likely to be spotted with my camera and tripod close by at night as I am by day. Not only do you tend to have places that by day might have hundreds if not thousands of people roaming around and taking similar photographs to yours, you also have an opportunity to see and capture light differently than most people ever will. After all, no matter what time it is you are creating an image; you are only capturing how the light falls on your subject. In fact the word photography literally means to draw or write with light.
At night subtleties of light and color are much more pronounced and the dynamic range of your scene (the difference from bright to dark areas) can be closer than daytime creating a surreal look that leaves your viewer captivated and often a little confused at the image they are presented with. Both of these images were taken at the same location a couple of days apart, and there is a dramatically different look to the same subject matter. In both images, the moon assumes a roll like the sun would in a daytime landscape. In the image above, clouds add to a sunset like effect and soften the light falling on the foreground.
Only when the eye travels towards the stars in the upper portion of the image does it become clear that this photograph was taken at night. In the image to the left, a mid to high aperture setting (in this case f8) creates the starburst exploding from the moon giving it a sun-like appearance. With no real cloud cover to speak of, the harsher less diffused light on the foreground creates much more contrast with the shadows giving a pronounced separation to the canyons and valleys.
In an urban environment, you have even more to consider
Here the moon phase won’t make as big of an impact as the differing colors of light present in a city. If you take a close look at the streetlights around at night, you will see ranges of yellows and oranges to more white and even greenish lights. Sometimes you have cloud cover to reflect the city’s ambient light and other times on a cloudless with nothing to bounce light back towards your lens you’re left with a black void behind your subject. All of these elements will play into your final image. The surrounding lights are casting a blue hue on some of the steel supports for the highway above while the other side is bathed in a warm yellow that contrasts against the blue. The red and green lights on the bridge and tower still have fine star points despite the lens being shot wide open. Had I used a higher aperture they would be even more defined. Those same red and green lights add all sorts of colored accents to shadows under the bridge. The high-tension wire’s frame is illuminated by the orange sodium vapor lights on the highway along with the more white headlights of the oncoming cars traveling above. This creates brighter spot that draws the eye to a simpler counterpart to balance the busy subject matter of the bridge. During day, this bridge and these power lines look just like that, a bridge and power lines. After the sun has set, this bridge scene explodes with color and subtleties that can only be captured at night.
The direction of light and shadow
Like daytime, at night the direction of light plays into the mood you are trying to create for the viewer as well. In the image on the left an aperture of f7.1 was used to turn the moon into a sun-like burst between the Moai of Easter Island. Over the 20 seconds this image took to expose quick moving clouds pass to create a streaky look. By exposing for more of the clouds than anything else in the image, the ancient statues take on a mysterious silhouette in front of the wispy clouds. At the top of the image the pinpoints of stars bring a motionless balance to the Moai.
By opening my aperture to f4, raising the ISO a bit and placing my light source (the moon) at my back, the same subject takes on a very different feel. Now the details of the statues become visible along with the foreground and stars. With the same shutter speed of 20 seconds, the clouds keep their wispy character.