Photon Counts
Photon counts are the discrete number of individual light particles detected by a sensor in a set time, quantizing light into integers rather than measuring continuous energy.
Photon counts refer to the discrete number of individual light particles (photons) detected by a sensor or instrument within a defined period. This measurement quantizes light into integers, distinguishing it from continuous energy flux, and is fundamental in fields like astronomy, quantum optics, and medical imaging where detecting low-light signals is critical.
What this means in real life
A smartphone camera's sensor counts incoming photons to determine how bright a scene is; more photons hitting the sensor in dim light means the camera boosts sensitivity to capture a clearer image.
What it isn’t
Not the same as measuring total light energy or brightness in watts. Photon counts focus on the number of discrete particles, not their cumulative power—a distinction that matters in quantum and low-light applications where individual photons carry meaningful information.
Commonly misused online
Often conflated with 'pixel brightness' or 'image resolution' on social media, when actually photon counts refer to the raw physical detection of light particles before any image processing occurs.