I don't know what they have done in the past, but I can assure you, the camera I have has one lense, takes one image, and captures green, red, and nir.  I have seen the spectral graph from the company for the camera.  There is only one set of images taken for each flight.  Once you read it into their software, they create 3 sets of images; NIR, NDVI (grayscale data), and NDVI (color).