Lens flange back adjustment
The lens flange back is an adjustment to focus in all ranges from the most telephoto to the most wide-angle of the zoom lens. Adjustment is necessary when using a zoom lens.
Lens flange back fixing knob
Lens flange back adjustment ring
Shoot a dark subject and open the iris all the way.
Set the distance to the subject to 2 m or more, and loosen the lens flange back fixing knob on the lens.
Set the lens to the most telephoto, and adjust the focus with the focus ring.
Set the lens to the most wide-angle, and adjust the focus with the lens flange back adjustment ring.
Adjust repeatedly with the focus ring and the lens flange back adjustment ring until it is focused within the zoom range.
Tighten the lens flange back fixing knob after the adjustment is completed.