what compression format is used by cameras with a 3:2 ratio and weighs less than 768.0?
(AND digicams.camera_compressed_format (JOIN (R digicams.digital_camera.compressed_formats) (AND (le digicams.digital_camera.weight 768.0^^http://www.w3.org/2001/XMLSchema#float) (JOIN (R digicams.camera_image_ratio.cameras) m.0220vcp))))