From a piece of fully-exposed then developed medium-format film, I made a filter that blocks visible light but allows infrared to pass through.
In the resulting photographs, foliage is lighter than tree branches.
n the resulting photographs, foliage is lighter than tree branches.
There are some issues.
First, very little infrared light is actually recorded. Both of these were 30-second exposures at ISO 400. The one of the left was at f/3.5 with +2 exposure in Adobe Camera Raw., the one on the right was at f/5 with +3 exposure. Motion blur from the wind on the tree branches and leaves is visible in these pictures, and fast moving subjects are out of the question.
Second, because different wavelengths of light refract differently, if you set the focus using visible light the infrared picture will be out of focus. You can sort of guess by turning the focus ring to the right a bit.
Third, the only color captured is a delightful fuchsia, shown below. They’re well suited for conversion to black-and-white.
Here are what the scenes look like in visible light.
