The technical jargon
Di (Digitally Integrated)
Is the designation Tamron puts on lenses featuring optical systems designed to meet the performance characteristics of digital SLR cameras as well as film cameras. These lenses may be used on cameras with full format (FF) or APS-C sensors (with a crop factor relative to the camera).
SP (Super Performance)
Professional class lens; currently the best lenses made by Tamron for the consumer market.