The Hoya 77mm Variable Density Filter provides excellent control over exposure settings, as it can change the amount of light entering the camera by 1.5 to 9 degrees. The precise design of the built-in double ring allows the outer ring to be rotated to adjust the effect of neutral density anywhere from 1.5 to 9. The double-ring design is slim to reduce the likelihood of vignetting with wide-angle lenses. This filter allows you to use many special effects, such as controlling the depth of field using a wider aperture or creating or controlling motion blur, as you can choose the right shutter speeds to achieve perfect blur. The HOYA variable density filter can replace different incremental ND filters, saving money and time as you only need to purchase one filter and do not have to change filters all the time to change the effect. Variable density filters are used, for example, to distinguish waterfalls, cars, and other objects from the background and to pay more attention to the object. Also in bright lighting conditions, such as on the beach or in a snowy day on a sunny day.
Be aware that when the filter is attached to the lens, the lens cap size becomes one size bigger. So if your lens has a filter thread size of 77mm, you will require an 82mm lens cap. The widened front filter frame has been designed on purpose to avoid vignetting.