When I’m out shooting at night, I am often asked: “How are you doing that in such low light?” I see many photographers put their cameras away in dismay grumbling something about high-ISO and image quality under their breath.
Night shooting can be tricky stuff. Exposure settings are critical, and the photographer must continually think about balancing the shadows and the highlights while managing each of the three exposure variables: shutter speed, aperture, and ISO. In these dimly lit night scenes, these settings may need to be used at their extreme, and worst performing, settings. Slow shutter speeds introduce the potential for motion blur, large apertures reduce the areas of the image that will be in focus, and high ISO settings produce digital noise. (If you are unfamiliar with how these three settings work, I’ve added an “Appendix” at the bottom of this post that describes them in more detail.)
Many photographers start pulling out their tripods for long exposures, leaning on a rails, or packing up completely. But because my street work focuses on human interaction and relies on nimble movement to find just the right angle, using a tripod is not really an option for me.
My solution, instead, is to use the constraints of darkness and light to add character and depth to the story I am capturing. I accept the digital noise in the shadows and the motion blur in the people. Indeed, a big part of my approach to all my photography is to seek story first and carry a carefree attitude of “image quality be damned” if the light is just not right.
It would be easy enough for me to leave the discussion here and just say: “Stop complaining, stop pixel-peeping, crank up your ISO, frame up your scene, and take your image.” But this would be a little disingenuous. There are some specific techniques and camera features that I use to get the best out the night.
- Pre-focus on the lit areas: The bright areas of the scene will provide the best contrast for your camera auto-focus. It will also be the areas that our human brains will hone in on in the final image. Pre-focus on the bright areas, then wait for the rest of the scene to play out.
- Camera or lens stabilization features: In addition to lenses with image stabilization (also called vibration reduction or optical stabilization) many of the newer mirrorless cameras have in-body image stabilization. In either case, using a lens or camera with image stabilization will help you reduce blur due to camera movement.
- Fast prime (single focal length) lenses: A “fast” lens is one with large apertures, f/1.8 or larger. (Remember, the smaller the number, the larger the aperture. For example, f/1.8 is a larger aperture than f/2.8). A prime lens is one with a single focal length (i.e. not a zoom). It is called “fast” because by opening the aperture, you can achieve the same exposure with a faster shutter speeds. In the digital world, as you open the aperture, you can choose to either increase the shutter speed or lower ISO to get the same exposure. Unfortunately, you won’t find zooms with apertures larger than f/2.8, and these zooms are larger and more expensive than a good fast prime.
- Shorter focal length lenses: The focal length of a lens provides its magnification power. However, with more magnification, there is more magnification of even small amounts of camera movement, resulting in blurry images. For night shooting, I recommend to sticking to the shorter focal lengths – 50mm, 35mm, 28mm. They have the dded advantage of providing better depth of field, being lighter, as well as being available with large apertures (see the previous principle on the use of fast prime lenses)
- Expose for the highlights: Exposing for the highlights typically means underexposing the image overall. While this may seem counter-intuitive for night photography when the scene is already quite dark, the camera metering system wants to expose the full scene to be an average gray forcing a scene which should be dominated by dark shadows to be mid-gray instead. Allowing the camera to average the scene will not only wash out the shadows and blow out the highlights, but it will also require the use of even longer exposure times, slower shutter speeds, and higher ISO values.
Capturing the nighttime stories that play out in pools of light and dark can be very rewarding. I say, forget about image quality. Go ahead a push you camera into new territories using fast lenses and higher ISO. Start looking at the images and not the pixels.
Learn more about making compelling street photographs with my book Life Happens in Color – A Street Photography Manifesto. Hear me talk about my photographic process on my interview with Ibarionex Perello on The Candid Frame.
Appendix: Explaining the exposure triad of Shutter Speed, Aperture, and ISO.
Exposure is controlled by 3 variables: shutter speed (how quickly is the picture taken), aperture (how much light is entering the lens), and ISO (the sensor’s sensitivity to light). Each of these variables has a unique impact on the rendering of the final photograph:
- Shutter speed: controls whether motion is stopped or blurred. Shutter speeds faster than 1/125th of a second are usually required to freeze the motion of people. Also, a slow shutter speed may introduce motion blur due to camera movement. As a rule of thumb, to avoid having the shutter speed impact image sharpness due to camera motion, it should be at least as fast as the fraction of a second represented by one over the lens focal length. That is, if you are shooting with a 50mm lens, the shutter speed should be at least 1/50th of a second. Often guides will recommend 2 times this minimum shutter speed, or 1/100th of a second for a 50mm lens.
- Aperture: controls how much of the scene is in focus at one time, also known as depth of field. Larger the apertures (i.e. small f-numbers such as f/1.8, f/2, or f/2.8) create shallower depth of field. Simplistically, the physics of optics dictates that if you focus on a very near object, distant objects will be blurry to some degree. Correspondingly, if you focus on a far object, close objects will be blurry.
- ISO: controls image quality and digital noise. Increasing the camera’s ISO tells the camera to electronically multiply the amount of light signal actually hitting the sensor. This is like a “gain” control on a microphone. Due to various properties of signal-to-noise physics, this creates color and intensity artifacts that might appear as speckles of light or color in the final image. Lower ISOs (ISO 100, 200, 400, 800) produce smoother and finer image detail. Higher ISOs (1600, 3200, etc…) can produce grainier looking images. The impact on the final image of high ISO settings will vary greatly across different camera makes and models.
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