Standard digital SLR cameras are equipped with
deep red cut-off filters which do not allow near
infrared (IR) photos to be taken. To get
around this, Hutech offers special dedicated IR
versions of selected
Canon digital cameras.
These cameras feature sensor-mounted visible
light blocking filters
(cutoff at 720nm) with special anti-reflective (AR)
coatings for the IR spectrum. In addition, the
system is re-tuned for correct operation of the
auto-focus (AF) function when adequate IR light
is available. Photos are composed using the
viewfinder in visible light. Manual focusing
is also possible after determining the IR focus offset
for the lens in use. The 40D features a live preview mode
which is convenient for focusing and composition using the
rear LCD screen.
Canon 5D and 40D
Visible light blocking filter used in IR cameras.