Buy B + W 77mm Infrared Filter # 093 (87C)B + W 77mm Infrared Filter # 093 (87C) Product Description:
Product Description
B & W offers three filters for infrared photography, each with its' own unique features. #092. This dark red filter is primarily for black and white infrared films. It filters out light below 650 nm. With color infrared film it produces pictures of a pure red image while making good use of the relatively low sensitivity of infrared films. Filter factor is approx. 20 - 40. #093. This black infrared filter will filter out the entire visible spectrum. It is used with black and white infrared films with a sensitivity up to 1000nm. Filter factor is determined by the film sensitivity. #099. This orange colored filter blocks the blue and blue-green portion of the visible spectrum up to 500 nm. It reduces the excessive sensitivity of color infrared films in this spectral range, separates colors more evenly thereby avoiding a blue tint. Filter factor depends upon the film's sensitivity.
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11 of 11 people found the following review helpful.
Infra Red
By Wade
This is a finely made filter. Brass ring and Schott glass. You really can't beat the Germans for optics. Build quality is top notch.Its hard to find something to explain how an IR filter works, but here is a brief explanation the Wratten scale and where this filter fits.Visible light ranges from 400 nanometers (violet) to 700nm (red). The table shows absorption limits for a range of infrared filters. This filter falls towards the end of the table.Filter AbsorptionWratten #25 600nmWratten #29 620nmWratten #70 680nmWratten #89B 720nmWratten #88A 750nmWratten #87 800nmWratten #87C 850nmWratten #87B 930nmAs you can see, this filter covers the high end of the IR scale. It takes extremely long exposures to get a usuable image. Most IR photos you see are done with a Wratten 89B filter. Its right at the middle of the scale and will effectively filter out all visible light. This 87C filter also filters out visible light, but also some IR light. This is what causes the excessively long exposures. You need alot of light to make this work.If you have patience, and don't mind spending quite a bit of time doing some trial and error, you can come up with some really nice photos.
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