ISO explained
ISO, or International Organization for Standardization, is a term that refers to the sensitivity of a camera's image sensor to light. When a photographer adjusts the ISO setting on their camera, they are essentially telling the camera's image sensor to be more or less sensitive to light. This can have a significant impact on the resulting photograph, and it is an important setting for photographers to understand and master.
One way that ISO can affect a photograph is by impacting the overall exposure of the image. When the ISO is set to a lower value, the image sensor is less sensitive to light, which means that the camera will require more light to properly expose the image. This can be beneficial in situations where there is plenty of light available, such as during the day or when shooting outdoors. However, if the ISO is set too low and there is not enough light available, the photograph may come out underexposed and too dark. On the other hand, if the ISO is set to a higher value, the image sensor becomes more sensitive to light, allowing the camera to properly expose the image with less light. This can be useful in low light situations, such as when shooting indoors or at night, but it can also result in an overexposed photograph if there is too much light present.
Another way that ISO can affect a photograph is by introducing noise or grain into the image. When the ISO is set to a higher value, the image sensor becomes more sensitive to light, which can also cause it to pick up more electronic noise from the camera's internal circuitry. This noise can manifest as tiny specks or grains in the photograph, which can be particularly noticeable in areas of the image that are supposed to be smooth and uniform, such as a blue sky or a plain wall. The higher the ISO, the more noise will be present in the photograph. This can be a trade-off that photographers must consider when deciding on the appropriate ISO setting for a given situation.
Finally, ISO can also impact the dynamic range of a photograph, which refers to the range of tones from the darkest to the lightest parts of the image. When the ISO is set to a lower value, the image sensor is less sensitive to light, which can allow it to capture a wider range of tones in the photograph. This can be beneficial for preserving detail in both the shadows and the highlights of the image. However, if the ISO is set too low, the photograph may lack sufficient contrast and appear flat. On the other hand, if the ISO is set to a higher value, the image sensor becomes more sensitive to light, which can allow it to capture a narrower range of tones. This can result in a photograph with more contrast, but it can also cause the shadows and highlights to become more exaggerated, potentially leading to lost detail in either the shadows or the highlights.
A general rule of thumb is to try to keep the ISO setting as low as possible. When trying to get a good exposure on your picture, it is typically (but not always) best to adjust your shutter speed and aperture as much as possible before making changes to your ISO setting.
In conclusion, ISO is an important setting for photographers to understand and master, as it can significantly impact the overall exposure, noise, and dynamic range of a photograph. By understanding how ISO works and how to adjust it appropriately, photographers can take control of their images and create the desired look and feel for their photographs.
