Sea&Sea FC Focus Gear for Canon EF 17-40mm f/4L USM Lens greenwaterfilter or weight typically associated with

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S-220 Strobe

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Sea&Sea FC Focus Gear for Canon EF 17-40mm f/4L USM Lens greenwaterfilter or weight typically associated withThis focus gear enables manual focus adjustment for the Canon EF 17 40mm f 4L USM lens via the Extension Ring 46 with Focus Knob #30117 when used with Sea&Sea MDX series housings. The focus gear is useful in the following situations: * When you need to manually adjust focus as your subject is not situated within the AF frame or in order to maximize the effect of the lenss minimal shooting distance of 28cm 11 inches. * When you shoot fast moving