The Cavision 9-Stop Density Adjustable Viewing Filter is a variable neutral density viewing filter with a 2x to 512x filter factor that lets you previsualize exposure according to your lighting conditions for movie and photography use. The viewing filter has a 1 to 9-stop density range, from 0.3 to 2.7, which enables use of this filter in situations ranging from the very dim to the exceptionally bright. While using this filter to previsualize your shooting scene, you can also compress the visual contrast to suit that of color film or digital sensors, which are much more limited than the contrast range of the human eye. This provides the ability to approximate lighting ratios and gain a better sense of how shadows and highlights will appear once recorded.
This viewing filter also features 37mm front and rear threads. The front threads allow additional filters to be attached to the front of the viewing filter, while the rear threads allow the viewing filter to be attached to other accessories such as a director's finder.