This JJC ND2-2000 Variable ND filter is designed with a built-in rotating ring that controls neutral density ranging from ND2 to ND2000 (1 to 11 f-stop). The heavier the density, the slower your shutter speed will be. It can reduce the amount of entering lights, but it does not change the original colors, which enables you to represent the photographic field. Another major benefit of this variable ND filter is the elimination of having to buy and carry around individual fixed ND filters. With this variable filter, you can rotate to the degree of ND you want, a real time and money saver. Note: When using this variable ND filter at high ND values (9 f-stop or above) on wide angle lenses, it would appear X cross mark, vignetting, or blur in the picture, this is unavoidable according to the structure and operating principle of a variable ND filter. If this is not acceptable to you, please go for a non variable ND filter, for example, a popular JJC brand fixed ND1000 10 f-stop ND filter. Why we need a Neutral Density Filter? -- It enables slow shutter speeds to be used, especially with high speed ISO, to record movement in subjects such as waterfalls, clouds. -- It decrease depth of field by allowing wider apertures to be used, which helps separate subjects from their background -- It decrease the effective ISO of high speed film (above ISO 400) and allow it to be used outdoors in bright situation -- It allows cine and video cameras (which have fixed shutter speeds) to film subjects such as snow, sand or other bright scenes which could cause overexposure It fits for any lens with 77mm filter thread, below are some lenses for your reference: Canon EF 24-70mm f4L IS USM / RF 24-105mm f4L / EF 17-40mm f4L USM / EF-S 10-22mm f/3.5-4.5 USM Nikon AF-S 16-35mm f4G ED VR / AF-S 24-70mm f2.8G ED Sigma 24mm f1.4 DG HSM Art / 17-50mm f2.8 EX DC Tamron 10-24mm f/3.5-4.5.......