Digital infra red photography
PetalsNWings
We are surrounded by electromagnetic radiation: from Gamma rays/X-rays on one end of the spectrum to radio waves on the other. We call a tiny slice of this spectrum "visible light". With wavelengths just a bit longer than the wavelengths of the radiation we see as red is "infra red radiation” (IR). The spectrum of IR stretches from "near" IR to "far" IR to "thermal" IR. It is the spectrum of near IR from which I make photographic images. (There is no "color" in my IR images, just black (no reflected IR), grays (varying amounts of reflected IR), and white (the most reflected IR)).
The sensors of all digital cameras are notoriously sensitive to IR. Camera manufacturers place an IR blocker in front of the sensor so IR will not degrade the visible light photographs taken with their cameras.
It is possible to make digital IR photographs without modifying the camera: One installs a visible light blocking filter in front of the lens thus letting the image be made by IR that "leaks" through the manufacturer's IR blocker. But, with this approach there are two severe problems: a) one can't see through the viewfinder to focus or compose making it necessary to focus and compose then install the filter, then make the exposure; b) the time it takes for enough IR to "leak" past the IR blocker in front of the sensor is considerable. One would have time for a cup of coffee between pressing the shutter release button and the completed exposure. A very sturdy tripod is mandatory. Hand holding the camera is impossible.
My IR cameras have been modified by removal of the IR blocker and its replacement with a visible light blocking filter. My IR cameras are blind to visible light and are very sensitive to IR. Focus and composition are accomplished normally through the viewfinder. Exposure times are very near what they are for visible light photography so hand holding the camera is the norm.
Since live greenery reflects the most IR, leaves and grass appear pure white. The sky often reflects little or no IR so it appears very dark or black. Practically every image is an unexpected treat for my eyes. Yours too, I hope.
The sensors of all digital cameras are notoriously sensitive to IR. Camera manufacturers place an IR blocker in front of the sensor so IR will not degrade the visible light photographs taken with their cameras.
It is possible to make digital IR photographs without modifying the camera: One installs a visible light blocking filter in front of the lens thus letting the image be made by IR that "leaks" through the manufacturer's IR blocker. But, with this approach there are two severe problems: a) one can't see through the viewfinder to focus or compose making it necessary to focus and compose then install the filter, then make the exposure; b) the time it takes for enough IR to "leak" past the IR blocker in front of the sensor is considerable. One would have time for a cup of coffee between pressing the shutter release button and the completed exposure. A very sturdy tripod is mandatory. Hand holding the camera is impossible.
My IR cameras have been modified by removal of the IR blocker and its replacement with a visible light blocking filter. My IR cameras are blind to visible light and are very sensitive to IR. Focus and composition are accomplished normally through the viewfinder. Exposure times are very near what they are for visible light photography so hand holding the camera is the norm.
Since live greenery reflects the most IR, leaves and grass appear pure white. The sky often reflects little or no IR so it appears very dark or black. Practically every image is an unexpected treat for my eyes. Yours too, I hope.
Great Blue Heron and "One Man's Treasure..." (PentaxK100D(IR converted) 300mm f/4.5 and 28-70mm f/2.8)
