The Tiffen 77 mm Variable Neutral Density Filter is used as a photographic tool for controlling depth of field and exposure. It has a built-in rotating ring that controls neutral density ranging from 2 to 8 stops. Its wider outer optic helps reduce vignetting at wide angles. This filter allows you to shoot high-speed films in bright-lit conditions, by reducing the ISO. Made of high-quality optical glass, this filter is built to last.