E.F. (Eelectronic Focus) - built-in electronic focusing system, these letters also designate lenses for use on full-format Canon EOS cameras
L (Luxury) - premium lens
FTM (Full Time Manual Focusing) - constant manual focusing
USM (UltraSonic Motor) - ultrasonic motor
Aspherical- aspherical elements in the optical design
Super UD (Super Ultra Low Dispersion) - the presence in the optical design of elements with ultra-low dispersion
IS (Image Stabilizer) - image stabilizer
IF (Internal Focusing) - internal focusing