In photography, ISO (International Organization for Standardization) refers to the sensitivity of the camera's sensor to light. It is one of the three key elements of exposure, along with aperture and shutter speed. Here’s a quick overview:

ISO Basics

• Low ISO (e.g., 100 or 200): Less sensitive to light, ideal for bright conditions and produces minimal noise.

• High ISO (e.g., 1600 or higher): More sensitive to light, useful in low-light conditions but can introduce some noise (graininess) in the image, but many of the resent cameras can handle shooting even higher ISO without producing noise. I shoot with my camera bodies in the 2000 range with no noise.

ISO and Exposure

• Low ISO: Requires more light, longer exposure time, or a wider aperture to get a correctly exposed image.

• High ISO: Requires less light, shorter exposure time, or a narrower aperture to achieve the same exposure.

Practical Usage

• Daylight Photography: Lower ISO settings (100-400) to maintain image quality and reduce noise.

• Indoor/Low Light Photography: Higher ISO settings (800-3200 or more) to capture enough light without long exposure times, which can cause motion blur.

• Action/Sports Photography: Higher ISO allows for faster shutter speeds to freeze motion without underexposing the image.

Balancing ISO, Aperture, and Shutter Speed

Adjusting ISO is often about finding a balance with aperture and shutter speed to achieve the desired exposure without compromising image quality. Here’s how they interact:

• Aperture (f-stop): Controls the amount of light entering the lens. A wider aperture (lower f-stop number) lets in more light.

• Shutter Speed: Controls the duration the sensor is exposed to light. A faster shutter speed reduces motion blur.

By understanding and adjusting ISO alongside aperture and shutter speed, photographers can achieve the optimal exposure and desired artistic effects in their images.