But there are times when you want to take unnatural pictures. I have written about such examples previously. One way to take unnatural images, is to photograph outside of the visible light spectrum, usually infrared.
Back in the film days, you could buy specialist film which was sensitive to infrared light. Normally, you would combine this with a visible light blocking filters, somewhat confusingly referred to as "infrared filters", to put in front of the lens. These filters block the visible light you see with your own eyes, only letting through infrared light. That way, you can photograph outside of the colours that you can see yourself, for interesting effects. These filters usually have a cut-off wavelength of around 650nm or higher, see the illustration below.
With digital cameras, this is somewhat simpler. The sensor itself is able to see infrared light, so you can use the normal live view process to compose your image, and even use autofocus. However, virtually all digital cameras have a strong infrared blocking filter built in. This is to avoid stray infrared light hitting the sensor, which would reduce the contrast.
Some specialist digital cameras come without the infrared blocking filter, for example the newly announced infrared version of the Fujifilm XT1. This camera is "full spectrum", meaning that you must yourself add a visible light blocking filter to the front of the lens to achieve the infrared effect. However, at a price of US$1700, this camera is not for everyone.
A cheaper option is to take a digital camera you already have, and convert it. This can be done by third party companies, or, if you are adventurous and dexterous, you can do it yourself. In this article, I show you how to do this with the Nikon 1 S1, an old, basic Nikon 1 camera. Contrary to what you may expect, this camera is serviceable, and you can disassemble it to access the filter stack above the sensor.
Nikon 1 S1 with Nikon CX 10-30mm VR in orange(!). There is a 760nm cut off infrared filter attached using a 40.5mm to 46mm step up ring and a 46mm to 52mm step up ring.
