1. The camera’s ISO setting. This tool controls the amount of light entering the camera by setting its sensitivity to light. ISO stands for INTERNATIONAL STANDARDS ORGANIZATION. This is an international group of people who decide what standards the world will use for most items that require numeration of some sort. The lower the number, the less light the camera “sees.” So, an ISO setting of 100 will be less sensitive to light than a setting of 800, say. If you are shooting in a situation where there is very little light, (at night, say), you might need to use a higher ISO number so that the camera can “see” more light. In many cameras equipped with a built-in flash, if you don’t change the ISO number, the flash will automatically pop up to add light to the scene. This would be undesirable in shooting a sunset, for example. So, if you don’t want to use the flash, you would need to increase your ISO setting.
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