Super Spectra lens coatings and lens component forming suppress flare and ghosting, more prone to occur with digital cameras due to reflection off the picture sensor. Coatings additionally help attain to genuine colour balance and expand contrast for clear vivid constancy pictures. The ring-type USM uses ultrasonic recurrence vibrations to drive greatly rapid autofocus with near-silent operation. A high velocity CPU and optimized AF calculations contribute further to AF speed. Full time electronic manual focus override is accessible without having to switch out of AF. The large maximum aperture of f/4-5.6 gives remarkable rate to shooting in low light conditions, without the need of flash. And the circular aperture createsa shallow depth-of-field that conveys focus on the subject and blur the background, which is perfect for portraits and weddings.