Geek Stuff

Night and Low-Light Photography: Digital Cameras

The idea

Long exposure photography is a means by which to take pictures at night (or in very low light) of subjects in a fashion which captures light in motion. The shutter stays open for longer than usual (some of my night shots have taken as much as eight minutes), and captures all the light which passes through the view of the lens. This allows the photographer to take pictures not otherwise possible, such as images which include the trail of lights from passing cars, or pictures which capture a variety of illumination on a given subject.

What you need

• A camera with manual settings I've taken night pictures with many kinds of camera, including digital and film. If your camera is of sufficient quality, it should have a setting called "bulb," which is what you want.
  
  
• A tripod, or some other way to keep the camera steady (there are a lot of different tripods out there, all with varying qualities which make them more or less useful in a given situation. Take your time and pick one which most suits your own needs). Usually, for low-light photography, you'll want wide-angle lenses; I haven't had any success with telephoto work on low-light photography.
  
  
• An adapter which allows you to open the shutter without moving the camera. This is commonly referred to as a "cable release" and is relatively cheap (I've seen used ones for $3.50 and new ones for as little as $4.99). Some modern cameras have remote controls which work equally well.
  
  
• A camera with the ability to turn off the flash. Flashbulbs only work within a certain distance. I've seen people try to use them to take pictures of fireworks. This is useless. Fireworks don't reflect light. They ARE light. Fortunately, no flash bulb is strong enough to illuminate the moon. If it were, we'd be burnt to crisps every time someone tried to use it.

Selecting a subject

You want a subject with a little bit of light on it, but not too much. You need it to be in a dimly lit area, without a lot of surrounding ambient light, but enough of a light source to make an imprint on the film. This can vary considerably, because some street lights are a great deal brighter than others. You may have to go through a few rolls of film before you get a good understanding of what works best. A nice first try might be a tree or mailbox or some other object on a local road which isn't very busy but has a couple street lights.

What to do

Set your film speed as low as it can go. Slower speed films (200 or lower) are better for when you have time to prepare the shot or are using a flash, or for outdoor shots on a very bright day. With my Pentax K10D, I use 100 speed, which is the lowest it will go. It produces crisp and clear images.

The reason for using slow-speed film in night photography is because even slow speed film will capture bright light at night, and the shutter can be left open for longer without overexposing the image.

You need to select an F-stop appropriate for the conditions: VERY low light means a lower F-stop. More light means a high F-stop. Ideally, the higher the F-stop the better, because it produces clearer images, but if your film speed is under 100 and you have very little light, you'll have to leave the shutter open for at least ten minutes to produce an image, and that's not always an option. Different cameras control the f-stop differently, so you may have to do a little reading if you're not familiar with these settings. The f-stop is a measure of how tight the aperture is, and the higher the number, the tighter it is. It also means better depth of field with higher f-stops. For landscape photography, including night work, it's best if you can go with as high an f-stop as possible.

You also need to remove any special filters you generally use on the lens. Night shots are best when taken pure-- no filters, no special tricks other than the camera eye itself.

Set up the camera with the tripod and make sure it's stable and sturdy. When you're ready, set your camera to bulb (on some cameras, this is listed as "manual"). You can use the adaptor to start the shot, and then hold it down, probably for at least a minute. Once done, use the adaptor to end the shot and try again.

What you want to do is to try varying the length of time you leave the shutter open. I.e., try a shot for 1 minute, then try it for 30 seconds, and then for 2-3 minutes. Contemporary digital cameras have the advantage of storing what's called EXIF data: small bits of information that can be accessed later which tell you shutter speed, film speed (ISO), f-stop settings, etc. This is extremely useful for digital photographers who are experimenting with low-light settings. It allows us to look at pictures later and see just how well our different exposure times translate to different qualities of shots.

Whatever else you do, don't be afraid to experiment, and don't be disappointed if you only end up with one or two good shots out of a evening of shooting at first. It takes time, practice and patience to learn to do this right.