sentences:  These cameras use the Sigma SA-mount, for which Sigma makes a line of lenses.The Sigma DSLR cameras that use the SA mount are the Sigma SD9, SD10, SD14, SD15 and SD1 Merrill.These cameras are noteworthy for their use of the Foveon X3 sensor, an image sensor that works on quite different principles from the sensors used in all other digital cameras.