Abstract: A photographic film camera adapted to receive a film cassette having a rotatable radial bar code data disk mounted at one end thereof is provided with a variable gain opto-sensor circuit responsive to the radial bar code for generating a sensor output signal having transitions through a logic threshold normally representative of transitions between data elements on the data disk. A microcontroller adapted to read the data from the data disk compensates for a noisy, corrupted by establishing a first gain setting and selectable other gain settings at the opto-sensor circuit during generation of the sensor output signal, and by counting logic threshold transitions in the output signal such that if the transition count for the first gain setting is other than a count corresponding to a fixed number of bar code data elements on the data disk, the opto-sensor gain is adjusted to one or more of the selectable other gain settings until the transition count corresponds to the fixed number of bar code data elements.