Digital photography has opened up a whole new world when it comes to setting the ISO speed on your camera. With a film camera you were bound to whatever film speed you loaded in your camera or carried with you in your camera bag; but with a digital camera, you can adjust the ISO on the fly, depending on your lighting conditions.
The ISO setting in your camera is the baseline that helps determine your aperture and shutter speed settings. It allows you to choose the camera sensor’s level of sensitivity to light. It also makes a big difference in image quality. With a film camera, the ISO is also called “film speed,” and the higher the ISO number, the grainier your images will be. With digital hotography, that grain is referred to as “digital noise,” but the principle is the same—the higher the ISO number, the more digital noise you will see in your image. As I mentioned earlier, digital cameras offer an amazing amount of flexibility when it comes to setting your ISO. This is very useful, but it can affect the quality of your images if you set the ISO too high.
Which ISO you choose depends on your level of available, or ambient, light. For sunny days or very bright scenes, use a low ISO such as 100 or 200. As the level of light is reduced, raise the ISO level. Cloudy days or indoor scenes might require you to use ISO 400. For low-light scenes, such as nighttime shots, you’ll probably need to bump up that ISO to 1600. The thing to remember is to shoot with the lowest setting possible for maximum quality.
There is also the option to set your ISO using the Auto ISO feature. I use this from time to time, but I don’t recommend new photographers use this feature until they have a strong grasp of how aperture, shutter speed, and ISO work together to produce a proper exposure. While quite powerful at times, Auto ISO can be confusing if you are not sure what your camera is doing.
SETTING THE ISO
- Activate the camera by lightly pressing the Shutter button.
- Press the ISO button on the top of the camera (Figure 1.2).
- Use the Main dial to select an ISO between 100 and 6400.
- Lightly press the Shutter button again to lock in your change.
SET YOUR ISO ON THE FLY
There’s an additional way to change the ISO without taking your eye from the viewfinder: When you press the ISO button, you will see all of the camera settings in the viewfinder disappear, leaving just the ISO information viewable. Use the Main dial to adjust your ISO, and once it’s at the preferred setting, it will remain locked in until you change it again.
You can also take advantage of the camera’s Quick Control screen to change your settings. This feature allows you to make changes to the shutter speed, aperture, ISO, and other settings while looking at the LCD Monitor on the back of the camera (Figure 1.3).