A:Answer I would advise using the Sigma Dock to make AFMA for a Sigma 150-600mm lens. Because the lens is not a Canon, I would not rely on the Canon camera being able tor recognize it in the future. Also, the Sigma Dock is a far more comprehensive adjustment. It is also far more complex and time consuming to complete. The Canon procedure conducted at two focal lengths and distances, for a total of 4 test shots. The Sigma dock needs 16 test shots, four focal lengths and four distances. Time consuming, but worth the effort.