What is low light photography? Like the term ‘low light’ itself, I suppose the definition is rather arbitrary, after all the photographer has to work with a range of light levels which form a continuum.
Perhaps, then, the definition of low light photography should rest on the techniques involved rather than anything else; perhaps we can say that we have entered the realms of ‘low light’ when we are forced to use a tripod or other camera support (and with the exception of very long-lens shots requiring a support in broad daylight).
Even this definition, though, doesn’t quite feel right. It seems rather clinical, and somehow fails to convey what we are seeking to achieve when we talk about low light photography.
So let us start with that. When we think about low light, what is it that we are hoping to capture?
For me, at least, the answer is something of the subtle and hidden tones associated with near-darkness, and moreover the feelings that these special times of day arouse in me. Whether it be the serene beauty of the period immediately following sunset, as the warm tones of the day fade into cool blue hues, or the magical quality of night-time, when the landscape is simplified and ordered by an unbroken black backdrop.
Long Exposure and Motion Blur
Low light photography by necessity requires longer exposure durations, from perhaps a few seconds during dusk, to many minutes in the black of night. And this means scope to capture movement in a manner which can’t be seen with the naked eye. From waves smoothed by time to a soft cotton-wool blur, to the lights on fairground rides describing their own patterns, the opportunities for creative exploration are boundless.
Capturing lightning is another exciting (although potentially dangerous) option in low light conditions. The technique is simply to work out the correct exposure for the time of day, then open the shutter, and hope lightning will strike before you have to close it again. If you’re lucky you may even catch multiple strikes in one exposure!
A tip here is to select a small aperture, which then requires an even longer exposure – as the longer the exposure, the more chance you have of capturing that elusive strike!
Calculating Exposure Duration
Before you even start – if you have the option, shoot in RAW! This will give you far more freedom to adjust your exposure at the computer later on. Learn more about file formats
Firstly, set your camera to Aperture Priority mode, and make a note of the shutter speed the camera’s light meter comes up with, as well as the aperture setting you have chosen.
Now switch to manual, and plug in the same aperture and shutter speed settings.
Take a test shot and review the image on your camera’s display. You will probably find that the camera has over-exposed the image somewhat, so double the shutter speed (halve the exposure duration) and try again.
Repeat this process until you are happy with the results. (It is also worth keeping in mind that your images usually look brighter on your camera’s display than they actually are.)
It is likely that you will at some point have to extend exposure duration beyond your camera’s maximum setting. In this case switch to ‘bulb’ mode (one press to open the shutter, a second press to close it) and time your exposures manually. It also really helps image quality if you use a cable release rather than pressing the button on your camera.
If you are shooting at dusk, remember that light levels will continue to fall, so do keep checking your images to ensure they don’t become too dark.
It is also worth noting that very long exposure durations suffer from something photographers call reciprocity failure. Ooohhh – sounds exciting! Not really, it simply means that the inverse (reciprocal) relationship between light intensity and required duration of exposure (halve the intensity and double the exposure duration) begins to break down. In practice this means that you will find that you have to significantly more than double your shutter speed to let twice the light in. Now that might sound wrong, and it is. Of course doubling the shutter speed will double the amount of light that enters your camera, it’s just that your camera’s film or image sensor isn’t able to respond to light with 100% efficiency, and – the less light is available – the more this issue is magnified.