The Infrared Filter - an overview

Infrared Filter

An infrared or IR  filter is a filter to remove visible light and only pass infrared light in different wavelengths.

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.

We have in stock IR filters from 37mm through to 82mm