Neutral Density Camera Filter Technical Information (IR+ND combo filter N.9-N1.5)
PANCRO ND is the result of a high vacuum coating of a metallic alloy thin film on one side of the glass. This is the same technology that is used to coat high end movie camera lenses with multilayer anti-reflection coatings.
PANCRO ND has certain properties that make it superior to other NDs on the market. Its thin, metallic film results in superior neutrality with a flat spectral curve ranging from 380 nm to 2000 nm. This neutrality enables Pancro ND to filter out troublesome Infra-Red wavelengths in the 800 nm-2000 nm range that are captured on DV cameras. The result is a true neutrality.
Pancro ND will not make the IR POP like some ND filters do.
We emphasize that each ND filter is manufactured on single-piece, optical-select glass, as opposed to laminated or dyed glass. We do not sandwich a gel between glass or use resins or plastics. Laminated glass can crack and separate. Resin and plastic can easily scratch. Our single-piece, optical-select glass is durable with superior parallelism and flatness.
In operation, PANCRO ND depends upon an absorption in and a reflection from its thin metallic film, exhibiting outstanding characteristics:
(1) Panchromatic. PANCRO ND is sensitive to all colors of the visible spectrum. When calibrated by a spectrophotometer at 2840K (indoor tungsten lighting), it experiences a color shift of only 16K towards red.
(2) Neutral. Like a partial mirror, PANCRO ND is partially absorbing and partially reflecting. Because of this neutrality, the overall appearance of the ND filter is a colorless, gray tone.
(3) Accurately Controlled. PANCRO ND is consistently graded every .3, .6, .9, 1.2, and 1.5 densities. All ND filters are manufactured for matched filter sets.
(4) Durable. The PANCRO ND coating is very tough and will not easily scratch. Passes Miltary Specification 13508C for government contracts.