You’re Not Afraid of the Dark, Are You?
Don’t head for the surface just yet, there’s plenty to shoot down here.
Photographers often exist in a very dark space. Most times physically, sometimes emotionally. We like broad daylight about as much as vampires do, and can be almost as extra about it. We don’t require that all our shots be shadowy and moody, but we do require that they be interesting, and that frequently demands mastery of low light photography techniques to optimize the quality of our images.
There is no one definite of a low light environment. The type of low light environment in which you are shooting will determine the techniques that will prove most helpful. There are several considerations that can help you identify which flavor of low light shooting is on the menu. How much difference in brightness is there between the lightest and darkest areas of your scene? Are you ok with blowing out highlights or crushing shadows? Is the whole scene dark, and you are looking to draw out subtle details? Are you shooting still or moving subjects? Is it actually bright by conventional definitions, just not bright enough for you to use fast enough shutter speeds to freeze motion? Be clear about your intentions for each image, and use the settings and equipment that will serve your purpose best.
Single shot high dynamic range photo, exposed for highlights with shadows brought up in post.
In a high dynamic range environment, there is a large difference in brightness between the lightest and darkest parts of the frame. Most of our nighttime street shooting falls into this category, as it often occurs in a city with streetlights, neon, and car headlights in most shots. One approach to this challenge is artistic: if you envision the final image as black and white, or if you are after a more dreamy and bloomed or softened aethetic, expose for the shadows and let the highlights blow. Vice versa if you want to allow the shadows to be silhouettes, expose for the highlights and crush the blacks. A more technical approach can preserve all parts of the histogram, but requires a stable shooting support (ideally a tripod, or a wadded up jacket on a railing in a pinch) and a still subject. By using bracketed exposures and compositing them in post, both extremes are properly exposed. This is done by taking three exposures at differing exposure compensations (-3, 0, and +3), then combining them in one image. Many digital cameras have a setting to do this automatically, so check your user’s manual for details (you can usually find it under “AEB”). As for the postprocessing, some programs such as Darktable will allow you to select the three images and use the “HDR” button to combine them for you. Alternatively, this can be done manually with layers in a program like GIMP.
In a more uniform low light environment, as we might encounter underground or in moonlight, we are more free to gather as much light as possible without concern for blowing the highlights. Sounds easy enough; tripod, long exposure, and let ‘er rip. This becomes tricky when moving objects enter the frame. Or does it…? Once again, intention matters. If you’re after a sharp image, you may need to compromise with a higher ISO for a shorter shutter speed. But maybe you’re after a more ghostly, ethereal vibe. In this case, a long shutter speed resulting in blurred movement can lend itself to a haunting masterpiece.
Long exposure shot using tripod, with intentional blur of moving people.
So why not just always crank the ISO? I like to think of my sensor as a lint roller. When a lint roller is brand new (analagous to high ISO), it picks up every tiny speck of lint on your clothes, along with the larger bits you were really after. As the lint roller becomes less sticky (lower ISO), it picks up just the larger bits and not every tiny speck of fabric fuzz. Those tiny fuzzy bits are noise, and noise is the price you pay for a high ISO. You’re going to have to clean up those fuzzy bits in post, or live with them in your image. Your editing program will likely have denoising tools, but the tradeoff is a small loss of sharpness.
A low light environment can be relative; there may appear to be plenty of light to our eye, but it is not enough to accommodate our primary purpose. This became very real for me when I was asked to shoot a women’s basketball camp. Action photos were specifically requested, so very fast shutter speeds were necessary to freeze motion and prevent blurry photos. Fortunately for me, the gym was very well-lit, but I still had to raise my ISO to compensate for my shutter speed, even when shooting wide open. It was a case of picking my poison; I could denoise my images in post, but there would be no way to recover from motion blur. I was very happy with the end results, and more importantly, so was my client.
High ISO allowed very fast shutter speed, denoised in post.
Low light photography presents challenges that have helped me develop as a photographer. It requires understanding of exposure, knowledge of the tradeoffs between settings, and forethought regarding the final images. Each time you do it, you will place another trick up your sleeve for the next time. Wake up early, stay out late, or go underground. Capture what happens when the lights go out.
