One of the great advantages of a digital image sensor is its extreme capability in low light. With a digital image sensor, you can work at light levels far below what is possible with any type of film. This sensitivity opens up a lot of photographic possibilities, such as shooting landscapes by moonlight. However, while your camera can be very sensitive to low light, your eyes might have trouble getting by when shooting in the dark. As such, you’ll need to employ some specific procedures when working in low light.
First and foremost, you need a camera that can perform well in the dark. While all digital cameras these days offer a range of ISO options (higher ISO means more light sensitivity) not all cameras are well-suited to shooting by moonlight, because on some cameras, as you increase ISO, you’ll see a marked increase in noise.
Unfortunately, the noise argument that transpires on most digital photography forums can be confusing, because a lot of people will look at a 100% view of their image – that is, one screen pixel per image sensor pixel – and decree that a camera is too noisy. However, when you’re examining individual pixels from a 12 megapixel sensor, you’re looking at individual dots that are far too small to ever see in print.
To accurately judge noise, you have to look at your final output, whatever it may be. If your final output is to crop a 100% view of an image, and post it online, then individual pixels might matter. But if what you’re ultimately aiming for is a web posting, or an 8 x 10″ print, then you need to create those final works before assessing the noise levels of your camera.
Currently, I would offer the rule of thumb that point-and-shoot cameras are unacceptably noisy for low light work over ISO 400. I have not looked at every point-and-shoot camera out there, and have not seen the very latest offerings from every vendor, but as of 3 or 4 months ago, I had not seen a point-and-shoot camera that could deliver acceptable low-light, high-ISO performance.
The latest generation of digital SLRs, on the other hand, are a different story. Entry level SLRs are very good low-light performers all the way up to ISO 1600. Some are better than others, but all are capable of delivering good results from this kind of shooting. Higher-end SLRs are even better, offering reasonable results up to ISO 3200. Obviously, you’ll want to test your camera’s capabilities before taking it on a long night-shooting excursion.
Once you’re out, figuring out how to focus, frame, and expose your shot can be tricky, but this article will walk you through the entire process. And check this out for a more extreme form of low-light shooting.