embrace the night
Night shots are much easier in manual, and here’s why
Night photography can yield some spectacular images, but it’s unlikely that your camera will be able to give you the results you want if it’s left on automatic. This is because the scene will contain a much greater brightness range than normal daylight. Today’s Nikon D-SLRs don’t have any trouble measuring the low light levels you get at night, but they do have trouble working out which parts of the scene to base the exposure on.
In regular daylight, the light source for the scene (the sun) is usually not visible. If it were in the frame it would completely dominate the exposure and everything else would come out as a silhouette.
At night, you don’t get the sun in the frame, but you do get countless miniature light sources, like streetlamps, neon signs and car headlights. These ‘mini-suns’ are far brighter than their surroundings, and dominate the camera’s exposure reading. Use auto mode and you’ll end up with some bright pinpoints of light surrounded by darkness.
You can use the camera’s EV compensation control to try to adjust the exposure, but the only really reliable way to get good exposures at night is to switch to manual mode. Once you’ve done this you can use trial and error to arrive at a good exposure for the scene. It might take a couple of attempts, but you’ll soon get a feel for different situations and the kind of exposure you might need. For example, for a busy city street light by floodlights and neon signs, you might find that an exposure of a couple of seconds at a medium aperture of f/8 is about right, but for darker suburban streets you might need to increase that to 30 seconds or longer.
Don’t use Auto ISO
Your Nikon’s Auto ISO option can be invaluable for shooting in low light with the camera handheld, because it will adjust the ISO automatically to give what the camera thinks is the right exposure. However, this means handing control back to the camera in a situation where you know it’s not going to give good results. It’s much better to put the camera on a tripod, because then you can use your camera’s lowest ISO setting for best quality, and it won’t matter how long the exposure is because the camera will be kept
perfectly still throughout. And the longer the exposure, the more likely you are to get spectacular traffic trails.
The length of the exposure will determine how far objects move through the scene (and the length of the trails they leave). You can adjust the length of the exposure by changing the lens aperture. A wider aperture will let more light through so that you can use a shorter exposure, while a smaller aperture can be used to produce a longer exposure in very bright conditions.