12Choose a clamp ring to suit your camera lens.Turn the knurled screw anti-clockwise to widen therear clamping interface. The clamp ring uses acollet design making it easier to compress.Squeeze the ring adapter slightly, then carefully fitit into the clamping interface.Fit the clamp ring over the camera lens. Turn theknurled screw clockwise to secure the clamp ring tothe lens ensuring that it is firmly attached and thatthe mattebox cannot slip.Use the clamp ring to mount the O-Box directly onto the camera lens.This type of setup is used when carrying the camera on the shoulderor when mounting it without camera rods. Four standard-size clamprings are available (see page 8).For more information about lens diameters visit OConnor Labs onlineat the OConnor website (see OConnor > Labs > ‘Lens Diameters’).13assembling the clamp ring