To remove any of the C33 lenses, set the lens distance scale to any distance greater than 4 feet. Hold the camera as shown. Grasp the lens and place the right forefinger on the lens lock release (yellow arrow), press up on the release, and rotate the lens counter-clockwise (in the direction of the red arrow). Let your finger slide over the lens lock release as you turn the lens, and also let the rangefinder dial and lens mount turn. After about 1/8 of a turn, the lens will lift out.

You can also set the lens on infinity before removal. This leaves the dots on camera and lens aligned and the lens can be replaced without adjustment.