Understanding the ISO Camera Setting

If you’ve ever used a digital camera, you might have noticed that it has an adjustable ISO setting. So what does the ISO camera setting represent, and how do you use it when taking pictures? The ISO in photography stands for International Organization for Standardization, a governing body that provides the standards for a wide range of industries. For the photography industry, the ISO standard dictates how camera manufacturers rate the sensitivity of their imaging sensors.

The digital ISO standard matches the old standard for film sensitivity, so an image sensor with an ISO of 100 will have the same sensitivity to light as 100 speed film. A higher ISO camera setting means the sensor is more sensitive to light. Each doubling of the ISO number represents a one stop increase in light sensitivity. Most digital SLR cameras will have ISO settings that range from 100 to 3200. Some of the latest generation of digital cameras can go even higher than ISO 3200.

The best image quality is typically achieved when you shoot at the lowest ISO camera setting. As the ISO goes higher, the noise level, sharpness, and color all start to degrade. Most photographs are taken using an ISO setting that is between 100 and 400. For things like low light photography or fast action, you will likely have to increase the ISO setting above 400. If you shoot at high ISO speeds, noise in the image may become an issue. Digital noise is very much like the grain you see in film. To reduce noise in the final photograph, people often process the image with noise reduction software to smooth out the picture. The downside to using noise reduction on an image is that you often lose detail as a result. So it is a balancing act when managing the noise while also preserving detail.

Imaging sensors are improving all the time. Today, we can shoot at ISO 800 and get the same level of image quality as an older camera at ISO 400. But even so, most photographers like to stay under ISO 400 whenever possible. This habit is hard to break and probably dates back to the film days when 400 speed film was the highest speed commonly available. To get the most out of your camera, you should experiment with the ISO settings to see how high you can go before the image degrades significantly. You can then use this information to adjust the ISO camera setting based on what you are shooting.