PR for People Monthly APRIL 2016 | Page 28

2. The camera’s shutter speed. This tool controls how fast the camera’s shutter opens and closes. The shutter is usually calibrated in numbers that range from 1 second to 1/1000th of a second or faster. If the shutter is allowed to be open for a 30th of a second or longer, the camera will not be able to stop any action. Most objects will be blurry unless the camera is placed on a tripod or other stabilizing device. Here is an example of an image where the shutter was left open for longer than 1/30th of a second:

The red and white lines are made by cars’ headlights and tail lights. They are blended together because a slow shutter speed was used.

The following image was made with a very fast shutter speed which was able to “stop” the action. Approximately 1/500th of a second:

3.The Camera’s Aperture: Each lens has a diaphragm which controls how wide the lens opens. This tool is calibrated in what is called F/STOPS. The “F” stands for focal length. I won’t get in to the mathematics associated with each f/stop, but suffice it to say that each major “stop” represents either a halving or doubling of the amount of light reaching the sensor, depending on which way you go. For instance, the widest aperture is usually f/2.8 or f/1.4 or f/3.5, depending on how big the piece of glass used to make the lens is. The larger the glass, the lower the “f/number.” So, an f/1.4 lens is larger than an f/2.8 lens. The larger the lens, the more light it can let in to the camera. We call this a lens’ speed. So, an f/1.4 lens is “faster” than an f/2.8 lens. The larger the f/number, the smaller the lens opening or “aperture” is. So, if the light is very bright, as on a beach or snow, you would need to “stop down” the lens to f/16 or maybe even f/22, to reduce the amount of light reaching the sensor. Conversely, if the light is very dim, you would need to open up the lens to f/2.8 so that the lens can let as much light in as possible.

Here is an illustration of lens apertures:

These are the main tools you can use to control the amount of light that hits the sensor. There are also other ways of altering the light that hits the sensor. Most digital cameras today have various modes from which to choose that change the quality of light after it hits the sensor. It can be sharper or fuzzier. It can be bluer or redder. It can have a hue (color tint) to it. There are probably another two dozen ways that your digital camera can record a scene. Instead of learning about them, most people just put their camera on "AUTO" and snap away. This won't allow you to make really powerful images, but it will take care of most normal scenes. Next month I will write about some of the other settings! Stay tuned!