This drop-in polarising filter reduces reflections from non-metallic surfaces, ideal for landscape and architectural photographers shooting in difficult lighting. It also has the effect of boosting colour, particularly for blue skies and green foliage. The intensity of the polarising effect can be varied by rotating the filter, using a convenient gearing mechanism built-in to its housing. The colour of the Canon PL-C 52 (WIII) drop in filter will differ from the colour of the body of super telephoto lenses other than the EF 400mm f/2.8L IS III USM and EF 600mm f/4L IS III USM. This will not affect performance and the filter holder is fully compatible otherwise. Benefits Reduce reflections from surfaces like glass and water Useful in landscape photography for eliminating glare from wet rocks Boosts colour saturation Polarising effect can be adjusted, for a natural look and feel Compact and portable, easy to take anywhere Maintains the weather sealed protection against dust and moisture What\'s in the box Canon PL-C 52 (WIII) Drop-in Circular Polarizing Filter Compatibility EF 200mm f/2L IS USM EF 300mm f/2.8L IS USM EF 300mm f/2.8L IS II USM Lens EF 400mm f/4 DO IS USM EF 400mm f/4 DO IS II USM Lens EF 400mm f/2.8L IS USM EF 400mm f/2.8L IS II USM EF 400mm f/2.8L IS III USM Lens EF 500mm f/4L IS USM EF 500mm f/4L IS II USM Lens EF 600mm f/4L IS USM EF 600mm f/4L IS II USM EF 600mm f/4L IS III USM Lens EF 800mm f/5.6L IS USM EF 200-400mm f/4L IS USM built in extender 1.4x RF 400mm F2.8L IS USM RF 600mm F4L IS USM RF 800mm F5.6L IS USM RF 1200mm F8L IS USM