Certified Professional Photographer (CPP) Practice Exam 2026 - Free CPP Practice Questions and Study Guide

A sensor is primarily a grid of tiny photodiodes. Photodiodes are semiconductor devices that convert light into an electrical current. In the context of image sensors, each photodiode corresponds to a single pixel in the final image; it captures the intensity of light that hits it and translates that information into a digital signal. This grid structure allows the sensor to gather and process light information across the entire image area simultaneously, creating a complete digital representation of the scene being photographed.

While pixels refer to the individual output points of an image, they are the result of the data processed from the photodiodes within the sensor. Filters are used in conjunction with sensors to manage color or other aspects of the light entering the sensor, and transistors are primarily involved in amplifying the electrical signals generated by the photodiodes, but they do not specifically refer to the grid structure of the sensor itself. Thus, photodiodes are fundamental components that form the basis of image sensors in digital cameras.