The Tiffen 43mm Water White Glass IRND 2.1 Filter is an ND filter with a 128x filter factor that provides a 7-stop exposure reduction. Its 2.1 density creates a darkening of the entire image, allowing you to photograph with a wider aperture or slower shutter speed than normally required. By increasing your aperture or slowing your exposure time, you are able to control depth of field and convey movement more easily. Neutral density filters are intended to not affect the coloration of the image and are ideal for pairing with other filters.
The design of this filter has been optimized for use with digital sensors and to promote nearly flat attenuation of visible light and infrared light. Due to imaging sensors' greater susceptibility to infrared light, compared to traditional film, color casts can occur when photographing darker subjects that require increased exposure times.
This filter is constructed from Water White glass for increased clarity as well as color fidelity. It is made using ColorCore technology, a process that involves laminating the filter substrate between two pieces of optical glass, grinding flat to a tolerance of 1/10,000th of an inch, and then mounting to precision metal rings.