At night in a city, virtually any city, the scene before you changes dramatically. In some locations the architecture and spirit of the city is merely enhanced, shown with a different, though recognizable look.
In other locations, the city at night transforms into a new place, sometimes brighter and more adventurous, sometimes more alive and mysterious.
Either way, making images of cities at night can allow you to often capture a “new city” with a different life than it has during the day. Making photos at night has its own challenges, but it's still subject to the same set of constraints as daylight photography; aperture, shutter speed and light sensitivity. The difference is, these constraints often push you and your equipment “to the edge,” compared to photographing the same city during the day.
Despite the advances in digital photography, with significant increases in high end sensors' ability to have an improved low noise/high ISO capability, the trade-off between depth of field, exposure times and image noise still exists.
In cases when noise is a problem two particular techniques offer potential solutions. First, we can reduce noise through image averaging. This technique uses multiple images to produce a single reduced noise image. Second, we can reduce noise through focus stacking. Rather than increasing shutter time or ISO sensitivity to keep the aperture small to have a large depth of field, photographers can stack multiple images together using focus stacking to increase the depth of field, yet use a wide aperture. I will discuss these techniques in future articles.
There is another constraint which comes up infrequently in cityscapes, but if you're in a small town with few lights, with a bright sky, it could come into play. The problem is star trails. If you make a long exposure to use low ISO and a small aperture to decrease noise while increasing depth of field, you should follow the “Rule of 600” in such a location. The rule is based on the fact you can only shoot for one second when utilizing a 600mm lens, before a star trail will occur. A 28mm lens will allow you to shoot up to 21 seconds before you'll see a star trail. The seconds you can shoot resulting in no star trail is less that 600/lens' focal length.
In order to shoot at night and make great images you're going to need some good equipment.
- Camera — At this time I recommend using a DSLR for night photography. There are mirrorless cameras generally up to the task, however, in focusing and viewfinder image quality, they still don't match the DSLR for night work, or any dark environment, at this time.
- Lens — You're shooting cityscapes, in other words, landscapes, so a wide angle lens fits the bill for these shots. As a travel photographer, I primarily utilize zoom lenses to reduce the volume and weight of the equipment I haul around, so my primary lens for night photography is my 24–70mm f/2.8, although I also often use my 16–35mm f/4.0 VR lens, as well. For full size DSLR's, a prime lens with a focal length of 14–50mm will work well, or for a DX or APS-C format, the equivalent focal lengths will be great.
Along with your lens, don't leave your lens hood in you equipment bag when shooting at night. Night photography in cities often means harsh lights lighting buildings from a variety of directions. You don't want such light streaming on your lens' front element from the side at angles which can lead to lens flare. The best and easiest way to eliminate flare is a lens hood.
- Tripod — Since most night photographs will utilize a shutter speed at which you can't successfully handhold your camera/lens, some form of camera/lens support is necessary. A tripod is the ideal support system, but there are marvelous locations for great night cityscapes which have banned tripods (They typically ban monopods too.)
For example, in New York, both the Empire State Building and the Top of the Rock don't permit tripods or monopods. In Paris, no tripods or monopods are permitted on the Eiffel Tower or Arc de Triomphe. One of the best solutions for camera support in these location is a bean bag. I've used bean bags for camera/lens support across the globe.
- Remote Shutter Release — With long exposures even using a tripod, it's better to not activate your shutter release manually which could shake your camera. A remote shutter release allows you to activate the shutter without touching and shaking the camera.
- Flashlight — I always keep a flashlight with me at night to help me see my equipment. While my camera's controls light up as desired, the lens, etc. is dark.
- Extra Battery and Memory Card — It's always a good idea to have an extra battery and memory card. Night photos being long exposures, for example, will use your battery faster than daytime photographs. If you use auto-focusing, at night it uses more power too, because it often hunts for the right focus.