ISO is a fundamental aspect of photography that determines the sensitivity of the camera's sensor or film to light. Both film and digital cameras use ISO to capture images in different lighting conditions. However, film ISO and digital ISO have some significant differences in the way they work and the way they affect the final image. In this blog post, we will explore the differences between film and digital ISO and why they look different.
Film ISO is a measure of the film's sensitivity to light. A higher ISO film can capture images in lower light conditions, but with an increase in grain or noise in the image. Film ISO ranges from 50 to 3200 or even higher, depending on the type of film. Digital ISO, on the other hand, is a measure of the sensor's sensitivity to light. A higher digital ISO can capture images in low light conditions without adding grain, but with a loss of detail and an increase in digital noise.
One of the reasons film ISO and digital ISO look different is because of the way they capture light. Film is a physical medium that captures light by reacting to the silver halide particles present in the film emulsion. Higher ISO films have larger silver halide particles that can capture more light, but with an increase in grain. Digital cameras, on the other hand, capture light using an electronic sensor that can amplify the signal from the sensor to capture more light. However, this amplification can result in digital noise that can affect the image quality.
Another reason why film ISO and digital ISO look different is the way they handle exposure. Film has a wide latitude for exposure, which means that it can capture a wide range of tones in the image. This latitude allows photographers to over or underexpose the film to achieve a certain effect. Digital sensors, on the other hand, have a limited dynamic range, which means that they can clip the highlights or shadows if over or underexposed. This can result in a loss of detail and affect the overall image quality.
In conclusion, film ISO and digital ISO have some significant differences that affect the final image. Film ISO captures light by reacting to the silver halide particles present in the film emulsion, resulting in an increase in grain. Digital ISO, on the other hand, captures light using an electronic sensor that can amplify the signal to capture more light, resulting in digital noise. The way film and digital handle exposure also affects the final image quality. Understanding these differences can help photographers and filmmakers choose the right ISO setting for their images and achieve their desired results.