1. Thermal camera lens
Infrared camera lenses are usually made of germanium glass. The glass has a high refractive index. It is only transparent to infrared light, but opaque to visible light and ultraviolet light, so it can be divided into plants and animals in a very dark environment. The infrared camera lens is compared with the ordinary germanium lens used in the ordinary camera lens. The reserves are not low, but the extraction of high-concentration germanium is very difficult, so the production cost of germanium lenses is relatively high, and the market price is often higher than that of ordinary camera lenses.
2. camera lens
The lens of an ordinary camera is usually made of optical glass, and its most specialized function is of course to refract light (usually called magnifying objects). Generally, optical glass is artificially synthesized. Ordinary cameras/camcorders underexpose infrared rays, the main reason may be the photosensitive element and lens. The attenuation of infrared light by ordinary lenses depends on the lens material, coating and the wavelength range of infrared light.
Generally, the transmittance at the near infrared end near visible light is still relatively high. In order to filter out the interference of stray light in the wavelength bands other than visible light, the photosensitive element of the camera/camcorder is usually equipped with a visible light passing filter, so that the infrared light is attenuated by the filter. Therefore, to play infrared rays with a normal camcorder/camcorder, you need to remove the filter.