ISO is one of the three pillars of photography alongside aperture and shutter speed. It is a measure of the sensitivity of your camera’s sensor to light. ISO stands for International Organization for Standardization, which is an organization that sets standards for various products including photography.
The ISO value of a camera can be adjusted to control how sensitive the camera’s sensor is to light. A lower ISO number, such as ISO 100, indicates that the sensor is less sensitive to light, while a higher ISO number, such as ISO 3200, indicates that the sensor is more sensitive to light.
When you increase the ISO, the camera’s sensor will amplify the light that it receives, which means that you can use a faster shutter speed or a smaller aperture to get a properly exposed photo. This can be useful in low light situations where you need to maintain a fast shutter speed to avoid camera shake or motion blur, or when you want to achieve a shallower depth of field with a wider aperture.
However, increasing the ISO also has a downside, which is that it can introduce digital noise or grain into your photos. This noise can make your photos look grainy, particularly in areas of shadow or in solid color areas. The amount of noise that is introduced will depend on the camera’s sensor and the ISO value that you use. Generally, newer and more expensive cameras have better noise performance at higher ISO values.
Here are some examples to illustrate how ISO works:
Example 1: Low ISO
Let’s say you’re taking a landscape photo on a bright sunny day. In this situation, you can use a low ISO value, such as ISO 100 or 200. This will allow you to use a slower shutter speed and smaller aperture to get a sharper image with more depth of field.
Example 2: High ISO
Now, let’s say you’re taking photos at a dimly lit concert. In this situation, you’ll need to use a higher ISO value, such as ISO 3200 or higher, to get a fast enough shutter speed to freeze the motion of the performers. However, you may notice some digital noise in your photos, especially in the darker areas.
Example 3: Auto ISO
Many cameras have an Auto ISO feature that will automatically adjust the ISO value based on the lighting conditions. This can be useful when you’re shooting in changing lighting conditions and don’t have time to adjust the ISO manually. However, keep in mind that the camera may choose a higher ISO than necessary, which can result in more noise in your photos.
In conclusion, ISO is an important aspect of photography that can help you achieve the proper exposure in a variety of lighting situations. However, it’s important to be aware of the potential downsides of using a high ISO, such as digital noise, and to use it judiciously to get the best results.