Thus, for manual focus well and zoom

The focusing rings are very well made, made of plastic and are placed and compressed by the focus ring on the lens. About a Lung teeth then the ring engages and sits firmly and without play the focus ring. If you press the serrations laterally it dissolves easily from the lens. Practically the fast aufschraubaren lever in 2 different lengths. With them you can delicately move the zoom ring. The fact that you can simply unscrew these levers, always can let the lens focus ring when one of the levers in the pocket is too bulky.

This is of course not only to focus but you can set this via the zoom ring on the lens. So order the best is 2. But carefully. When Canon 24-105mm 4L lens have zoom and focus ring on the lens different diameters. The focus needs an FRG 14, the zoom ring a FRG 13 .. With 5mm play between the minimum and maximum diameter must measure the lens already or look in the table of the manufacturer (best is the moment when a seller who has a large Action House offers ...). Therefore, the filter diameter is allowed hernehmen under no circumstances, to order the Foton. Who does not have such data nor calliper which just puts a strip of paper around the focus and zoom ring and tried the mathematical formula circumference = 2 x pi x radius.