An infrared filter is a filter to remove visible light and only pass infrared light in different wavelengths.
Here are some types of IR filter to choose from:
• The Kodak Wratten 87, 87A, 87B, 87C (87 starting at 750nm, 87C at 800nm, 87B at 850nm, 87A at 950nm)
• The Hoya R72 (High quality filter starting at 720nm, which includes some visible light)
• The Hoya RM90 (High quality filter starting at 900nm)
• The Hoya RM100 (High quality filter starting at 1000nm)
• The M&K 1000 (High quality filter starting at 1000nm)
• The M&K 093 and 095 (starting at 830nm)
When these filters are used together with infrared-sensitive film or sensors, very interesting “in-camera effects” can be obtained; false-color or black-and-white images with a sometimes lurid appearance known as the “Wood Effect“. There is no doubt that infrared B&W photos have some dreamlike magic as these photos tend to be even more abstract than usual B&W photos. An impressive amount of detail shines through the haze in the IR image on the right, despite the odd false-color scheme.
Notice that Objects at room to body temperatures don’t glow in the NIR any more than they do in the visible band. The 2 most commonly encountered NIR sources are the sun and incandescent (tungsten) lighting. The effect is mainly caused by foliage (such as tree leaves and grass) strongly reflecting in the same way visible light is reflected from snow.
The other attributes of infrared photographs include very dark skies and penetration of atmospheric haze, caused by reduced Rayleigh scattering and Mie scattering (respectively) in the atmosphere compared to visible light. The dark skies, in turn, result in less infrared light in shadows and dark reflections of those skies from water, and clouds will stand out strongly. These wavelengths also penetrate a few millimeters into skin and give a milky look to portraits, although eyes often look black.
In other words, generally, objects that appear quite dark at visible wavelengths may be very bright in the near IR.
Some cameras are designed to be more infrared sensitive: Minolta Dimage 7 (D7), Nikon CoolPix 950, Oly C-2020Z, Oly C-2000Z, Canon Pro70.
If you are interested in infrared photography on film camera, read this article and take this under consideration too.
Chromasoftware launched their interpretation of a Photoshop IR filter. The plug-in emulates the look of the infra-red film and it’s designed to be usable with the landscape photos as well as portraits. You can download a demo version from Chromasoftware here.
[tags]IR Filter , Infrared Photography, Chromasoftware, Hoya[/tags]