Helping to selectively reduce exposure in certain areas, while allowing for a normal, unaffected exposure in other regions, the 77 Formatt-Hitech Firecrest Graduated ND Filter is ideally suited to controlling bright skies without underexposing the foreground. The filter is densest at the edge and tapers to clear by the middle, with a soft-edged line of transition between the density and clear areas. The filter is mounted within a rotating frame, and allows for greater control over the orientation of the density to match certain subject types. Neutral density filters do not affect the coloration of the image and the 1.5 optical density provides a 5-stop reduction in light from entering the lens.
The design of this filter has been optimized for use with digital sensors and promote nearly flat attenuation of visible, UV, 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 provides a high level of neutrality across all three spectrums in order to eliminate color casts and ensure cleaner, truer blacks.
Applied to the outside of the Schott Superwite glass construction is a 15-layer Firecrest multi-coating, which helps to minimize reflections and flare in order maintain truer colors and contrast. The multi-coating is also scratch-resistant and hydrophobic to benefit the overall durability of the filter. The filter is set within a 7.5mm-thick SuperSlim aluminum filter ring, which features front threads for stacking additional filters or attaching a lens cap.