The 58mm Conical Step-up Ring with 85mm Outside Diameter from Cavision is an AR series, conical adapter ring. The ring screws onto the front of a lens with 58mm filter thread and provides an 85mm O.D. surface for mounting a clamp-on matte box. Conical rings are intended for special purposes – for example – if the camera has a low overhanging microphone and the matte box needs to be pushed further out in front of the lens. The ring has a depth of 0.79" (20mm).
58mm rear thread (male)
85mm outside diameter
0.79" (20mm) depth