The 10" F10 Barndoors for the LS 600d Fresnel Attachment from Aputure offer a means to control the 15 to 45° beam spread range of the Fresnel.
Categories:
Modifiers
Swing one or more leaves into the beam path to light areas you want and to keep light from areas you don't want illuminated. The 8-leaf design gives even greater control than 4-leaf versions and provides clean cuts of light.