The 52mm Drop-in Filter Holder from Canon is used with super long telephoto lenses that accept 52mm screw-in filters. The holder drops-in to the rear of long Canon lenses and is easy to insert and remove.

Compatibility

EF 200mm f/2L IS USM
EF 300 f/2.8L IS II USM
EF 400 f/4 DO IS USM
EF 500 f/4L IS II USM
EF 600 f/4L IS II USM
EF 800 f/5.6 IS USM