An optical reader having an array of differing-color light sources and a controller for controlling the light sources and acquisition of optical data. The light sources are arranged, and the controller is configured, to allow rapid acquisition of optical data regarding individual sample wells of a cluster of such wells. In some embodiments, multiple ones of the differing-color light sources are illuminated simultaneously for acquiring optical data on a corresponding number of sample wells. Depending on the configuration of the array and number of differing-color light sources illuminated simultaneously, the optical reader can acquire optical data for several wavelengths in a fraction of the time of conventional optical readers. Other embodiments include one or more non-contact temperature sensors for acquiring temperature data substantially simultaneously with the optical data. The temperature data can be used, for example, to adjust the optical data or warn a user of out-of-specification temperature conditions.