The zoom ring can be locked to fix the lens at the shortest setting. This function is convenient for carrying a camera on the strap because it prevents the lens from extending
To use the lock, turn the zoom ring to the widest position (70mm)
The lock can only be set at the widest setting
Slide the zoom ring lock lever in the direction indicated by the arrow
To release the zoom ring, slide the zoom ring lock lever in the direction opposite to the arrow.