What is Infrared Photography?
In infrared photography, the image sensor used is sensitive to infrared light. The part of the spectrum used is referred to as near-infrared to distinguish it from far-infrared, which is the domain of thermal imaging. Wavelengths used for photography range from about 700 nm to about 900 nm. Film is usually sensitive to visible light too, so an infrared-passing filter is used; this lets infrared (IR) light pass through to the camera, but blocks all or most of the visible light spectrum (the filter thus looks black or deep red). (“Infrared filter” may refer either to this type of filter or to one that blocks infrared but passes other wavelengths.)
Converted Digital Cameras vs External filter
Infrared images taken with a none converted camera and external (lens) infrared filter will require extreme long exposures and in the higher wavelength even be blocked. To better use the complete spectrum of infrared the camera sensor need to be converted to full spectrum. The sensor is now sensitive to the complete spectrum up to 1000nm and in some cases above this. So i n short, you always need to modify your camera to full spectrum to record Infrared light.
Why convert to full spectrum?
In a full spectrum conversion, the camera’s sensor mounted hot mirror is removed and replaced with a clear glass filter or no filter at all. This makes the camera sensitive to UV, visible, and IR light. This gives you the flexibity for various external filters, the camera can take pictures of regular light, infrared light, UV light, or any other combination of these. Most hot mirrors also have an anti-aliasing filter built in, so by removing this filter pictures will be sharper. Big advantage of full spectrum is flexibity in the spectrum. But be carefull in SLR camera’s full spectrum have the disadvantage of looking through the lens, so with lens mounted filters like a 920nnm filter, you will see NOTHING through the eyepiece. You must use the camera’s build in live view function. This disadvantage is not present in system camera’s for both the eyepiece as the display you will look at a picture that is recorded by the sensor.
Uses of Infrared and Full Spectrum Photography
Infrared will enable you to take pictures of landscapes, people or other objects that will turn your images in fine art. The full spectrum also let’s you image the nightsky, like for example the galaxies or nebula but also Ultraviolet images that will enable you to image the skin defects or sunscream effectiveness, but also the old wet colodian photo’s.