By: Joseph Grosjean
Photographer and Photograph Editor
Last issue we discussed how an aperture controls the amount of light entering the camera body, as well as depth of field effects.
This issue we will explore the purpose of the shutter in a camera, and the effects that can be created with a proficiency in shutter control.
The shutter is in the camera body and its original purpose was to keep film from being exposed before the photographer wants to take the photograph, sort of like keeping the film in a dark room, then opening the window blinds for a split second.
Due to the sensitivity of the film this small amount of time is enough to create an image, and this process will be discussed in more detail next issue.
This principle is still used in modern digital cameras which allows the use of higher efficiency image sensors.
Some camera manufacturers have experimented with cameras without shutters.
The benefits of this are lighter camera bodies, and no “clacking” of the shutter when you take a photograph.
The drawbacks are that there must be control over each pixel in the image sensor which makes these camera bodies expensive compared to their shuttered counter-parts.
The shutter is the second of the three points on the exposure triangle, the first being the aperture.
If an aperture can be compared to a pipe of different diameters, with a larger diameter pipe allowing in more light, and a smaller diameter pipe allowing in less, then the shutter is comparable to a valve, allowing in a precise amount of light.
Too much and the image will be overexposed, in other words the image will appear too bright, possibly completely white.
Too little light and the image will be underexposed, or too dark. The goal of a balanced exposure is to avoid both extremes, and the ways to accomplish this will be discussed in a later issue.
Now you wish to take a photograph. As a photographer it is your job to ensure that the image you produce is interesting, otherwise people will not be drawn to your work.
This can be accomplished through lighting, framing, depth of field effects, and many other techniques that can be used to create breathtaking images.
The shutter speed plays a large role in this artistic side of photography, and you must think, do I want the image to be sharp and crisp, capturing a tiny sliver of time, or do I want to create a sense of motion by allowing parts of the subject or background to be blurred out. This is what you must consider before taking a photograph.
Typically, your shutter speeds will be in the range of 1/80 – 1/4000 of a second depending on the desired effects, the environment, and your other settings, but anything under 1/80 of a second will be subjected to motion blur.
Motion blur is not always a bad thing, as listed above, and one of the best techniques that uses motion blur is called panning.
In this technique a slow shutter speed is used, around 1/15 – 1/30 of a second.
The photographer pans the camera to keep the subject (moving) centered in the viewfinder as the image is taken.
The effect this creates is a frozen subject and a streaked background, which creates an exaggerated sense of motion.
Mastery of the shutter is one of the most important skills a photographer can master and is the setting that is changed most often from photograph to photograph.
Next issue we will investigate the last point on the exposure triangle, ISO or ASA, and both film and digital methods of capturing images.