Three Pillars of Exposure (Part 2): Shutter Speed

Picture yourself outdoors with a camera in hand, crouching to capture the image of migrating birds in the sunrise. Dawn is breaking, it’s dim, and unfortunately there’s very little you can do to control the lack of sunlight. Therefore, learning to master your camera settings and how to expertly adjust them in overly dark situations (and sometimes overly bright) is vital to becoming a superb photographer.

As mentioned in Part 1 of this blog series, there are three specific settings that are often referred to as the three pillars of exposure: ISO, shutter speed, and aperture.

What is shutter speed?

Shutter speed is also known as exposure time. It’s the length of time that the camera shutter is open to allow light to fall onto the sensor. It’s given in fractions of a second, for example 1/60, 1/200, 1/3000, etc.

When you look through your DSLR viewfinder, you’re looking through a series of mirrors that get their light directly from the opening of the lens. When you press the shutter release button, this causes the system of mirrors to flip up over the sensor and the curtains of the shutter mechanism to open, thus controlling the amount of light. This mechanism also creates that familiar clicking sound when your camera takes a photo. And why your camera goes black for a moment in between photos, as the shutter mechanism readjusts. An average DSLR camera has a lifetime wear of over 100,000 shutter releases. Some high-end cameras have a lifetime wear of over 300,000.

A slower shutter speed allows more time for light to fall onto the sensor. A faster shutter speed allows less time.

If the shutter speed is fast, the resulting photo will freeze the action in time. If the shutter speed is slow, it will capture a blur in the motion. The blur may be caused by two things: camera shake, or movement of the subject. Sometimes a blur in the photo may be desired for artistic reasons – such as capturing the fluttering of a bird’s wings.

Tip: If the shutter speed is fast, the resulting photo will freeze the action in time. If the shutter speed is slow, it will capture a blur in the motion.

High shutter speeds are necessary for those handheld shots when you’re viewing an animal in motion and you want tack-sharp focus, or shooting from a moving vehicle. In these circumstances, it’s handy to put your DSLR camera into shutter priority (keeping the number high), which allows your camera to automatically adjust aperture for the best exposure.

The photo of this bird, a female red-winged blackbird, was taken at a shutter speed of 1/2000 in the sunset, with the camera set on shutter priority because the bird could have taken flight at any moment.

Slow shutter speeds are necessary for dimly lit times such as cloudy days or dusk. However, if you allow the shutter speed to go too low, it becomes impossible to control camera shake and the resulting photos will all be blurry. One solution is to use a tripod. Another might be to increase the ISO number. A third option, to be discussed in Part 3 of this blog series, is to adjust the aperture.

Have you experimented with different shutter speeds? Have you tried shooting in shutter priority on your camera? It can be a lot of fun.

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