Disadvantage:
1. If the strap is attached, it is always in conflict with the lens hood. When pulling out of his pocket (the lens hood I never screw to the lens to prevent damage to the plastic bayonet of the lens hood) draws the Sterulichtblende the cover using the strap. The problem probably true only pockets in which the camera along the optical axis is pulled out.
2. The loop does not pull tightly around the lens itself, ie, the stop is not particularly safe.