Sigma 150-500mm lens collar

A collar to fit around the exposed shaft of the Sigma 150-500mm lens when extended to 500mm focal length.This is an awesome camera lens but unfortunately it can not be locked at a given focal length an the heavy glass elements causes the lens to extend or contract on its own if not held level. It also doesn't hold focus as it focal length changes. So for astrophotography, wildlife and sporting photography you can miss a good shot because the lens has crept from its position.

This Thing is a