One disclosed embodiment includes detecting flicker in a photographic setting. A plurality of samples are obtained from a light detector circuit of a camera, each of which has a value that is dependent upon intensity of light incident upon the camera. The method further includes processing the samples to identify whether the incident light is varying in intensity at one or more pre-selected frequencies. The processing may include multiplying the samples with one or more periodic signals to generate scalar product outputs, and analyzing the scalar product outputs to ascertain the presence of periodic flicker.