Underneath the zoom ring are two metal rings with teeth on one side of them. In between the metal rings are 3 plastic gears. Those gears are referred to as the reverse gears.

Remove the two M1.7x3mm JIS #000 screws holding in one of the reverse gears.

Use a pair of tweezers to pull off the reverse gear.

Repeat the previous 2 instructions to remove the other two reverse gears.