Picking up a DSLR camera for the first time can be intimidating – unless you flip the switch straight to “auto” and never look back; but what fun is that? Gaining control and discovering how to create what you want to see is one of the most exciting parts of photography. It is also getting easier to gain this kind of control with point-and-shoot cameras; so even if you don’t own a DSLR, you can still gain a lot from this article.
The “auto” setting is not recommended for control. Control requires an understanding of three key aspects: aperture, shutter speed and ISO. One of the larger goals in capturing a great photo is accurate exposure (resulting in an image that is not too bright or dark), and the auto mode is a way of making your camera guess how to accurately adjust the settings for any situation. If you have any experience with technology, you know the auto setting is not always great at guessing correctly.
Aperture: If you happened to catch my column last week, you know all about aperture and how to control the amount of available light reaching your camera’s sensor. Setting the aperture to a low f-stop (e.g. f/2.8) will allow higher levels of available light to enter your camera and reach the sensor compared to using a higher f-stop (e.g. f/10).
Shutter speed: The shutter speed refers to how long the camera shutter will stay open, measured in fractions of a second. For example, a quick shutter speed may be 1/8000 (one eight-thousandth of a second).
ISO: ISO refers to your camera sensor’s sensitivity to available light. The sensitivity of the sensor is lower at lower ISO levels. This will, in most cases, cause the photo to appear darker than if the ISO is set to a higher value.
Aperture, shutter speed and ISO are like a technological triangle. They all need to get along with each other for you to create what you desire. Like anything, this comes with practice, but your camera is designed to help.
This triangle is best illustrated by description of two settings that give the photographer more control while maintaining guidance from the camera and sensor. These are the “aperture priority” and “shutter priority” modes. In aperture priority mode, the shooter can choose how open the aperture is (by means of the f-stop setting). The camera then will choose the shutter speed that best accompanies that particular aperture, based on how much light is available. If the environment is darker, the shutter will stay open much longer than it would in a lighter environment to gather all the light information it can. The opposite happens in shutter priority mode: the photographer chooses how long the shutter is open and the camera chooses the appropriate f-stop for the aperture. Basically, the wider the aperture, the more light allowed to reach the sensor, and the shorter the shutter speed needs to be to get sharp images.
Blurry, underexposed or overexposed images happen when aperture and shutter speed don’t “get along,” and ISO comes in handy here. Increasing the ISO will reduce the camera’s sensitivity to light. This will help compensate for the natural shake of a camera when taking a photo (causing blur), while lowering the ISO can compensate for the lack of available light coming in through the aperture (avoiding underexposure). But be careful: if the ISO is set too high, a photo may be overexposed. ISO is a great tool, but if it is not used wisely it can significantly downgrade the quality of your photographs.