Night time and low light photography
A camera-mounted electronic flash at night, even when correctly-used, often overexposes the immediate foreground and leaves the background in darkness. When that sun goes down at dusk, photographers have to rely on other light sources to obtain their images. There are two basic types of night photography: ambient light photography (also called available or existing) and artificial light photography. Ambient light may also be artificial (street lights, neon signs, etc.), but the term “artificial light photography” when used here refers to light introduced by the photographer, such as electronic flash illumination.
Ambient light photography
Existing light in a night scene can be difficult to figure out what exposure settings to use for it. When a scene is lit by the sun, a general exposure reading will usually provide decent results, but when a scene is mainly dark and there are different sources of light illuminating it at different strengths, the photographer is challenged to obtain the correct exposure.
Using automatic white balance at night may produce results that are difficult to predict. For instance, a subject illuminated by fluorescent lighting will appear to be greenish when photographed using a normal daylight white balance or even using automatic white balance.
Ambient light at night is often sufficient for people to just make things out or for a specific purpose. A car’s headlights, for example, illuminate the road in front of it, but do not illuminate the car itself or very much else. Street lights have a limited range. A town at night has bright spots and dark spots. A restaurant table may be lit by a single candle, or may be brilliantly illuminated by strong interior lights. A field may be illuminated by a bright full moon that provides only a fraction of the sun’s light, making some shadows look blue and providing sharp contrast between highlights and shadows.
When the ambient light is bright enough, it may permit sufficiently-fast shutter speeds for hand-holding your camera. Frequently, the light source itself is the subject, as when photographing fireworks. When you are shooting light itself – not what it is illuminating – shutter speed is a major consideration, especially if the light is in motion. A long, slow shutter speed will allow a light to move across the scene for a longer period of time while the exposure is being made, tracking the light’s movement in a line across your cameras sensor. The snaking tail-lights of a moving vehicle is an example.
When using ambient light, a photographer must contend with a wide variety of lighting situations at night. Low light photography is challenging, but once you have learned how to achieve good night pictures using existing light, it can be highly rewarding.
Artificial light at night
The most common form of artificial light produced by photographers today is electronic flash.
Flash during daylight hours is primarily used for “fill flash lighting,” that is, supplemental lighting to brighten shadow areas when shooting a subject in another light source, which is typically the sun. Flash at night does not usually have the benefit of another powerful light source to provide illumination in areas that the flash’s light does not reach, and many night-time flash pictures have very dark backgrounds because there is simply insufficient balance between the flash’s illuminance and the feeble light falling on the background.
When exposing for light itself and when that light is significantly brighter than its surroundings, the rest of the image will probably be completely dark. As seen in many photographs taken in a bar or night club when taking snaps of friends on a night out.
Photographers using bright artificial lighting on a foreground subject at night must compose their images to take into account that far-off background objects that they can see may not be visible since the objects will be underexposed. The light from a single flash unit will simply not reach them, as light falls off very quickly over distance. Sometimes, this is a benefit, since bright flash illuminating a foreground object may be all you want, and a dark background may suit your composition perfectly. At other times, however, you may need to re-position your subject or your flash to provide sufficient illumination for everything that is important to the composition. alternatively you can use a second flash, triggered by your on-camera flash to add light to the background.
Direct flash can provide flat, uninteresting images. Bouncing flash off walls or low ceilings can provide more pleasing results. The shot above was achieved using an off camera flash positioned at 45 degrees to the subjects, and pointed directly at them. It illuminates the couple in a much more flattering and pleasing way then would an on-camera flash, which would provide enough illumination but would be directed from the cameras position. Notice how very little of the artificial flash has spilled onto the background, leaving the ambient background lighting intact. However the exposure of this particular shot has been made to keep the background illuminated enough to see the detail of the room.
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