Canon EF 200-400mm f/4L IS USM Extender 1.4X User Manual - Page 23

17. Drop-In Filters A 52(WII)-series drop-in gelatin filter holder with a glass filter is included with the lens. The dropin filter holder can be used fitted with a gelatin filter (sold separately). 47mm 14mm 14mm To remove the drop-in filter, press in the left and right lock buttons and pull the filter holder straight up out of the slot. To install the drop-in filter, push the filter holder straight down into the slot until it clicks into place. ●● The filter holder can be installed facing either forwards or backwards. Because the lens optics are designed to include a glass filter, you must always install the filter holder, even if no gelatin filter is fitted. 47mm Lift up the holder's retaining plate. Cut the gelatin filter as shown and mount it in the holder. Return the retaining plate to its closed position. The Drop-In Screw-Type Filter Holder 52(WII) and Drop-In Circular Polarizing Filter PL-C52(WII) are also available (sold separately). ENG-22