Why are lenses with the same focal length divided into ordinary lenses and infrared lenses? What is the difference between ordinary lens and infrared lens?
In a surveillance environment that does not require infrared light assistance, you can use an ordinary lens; in a surveillance environment that has infrared light assistance, you must use an infrared lens if you want to have an ideal monitoring effect. Of course, you can also see the picture with an ordinary infrared lens with infrared assistance, but the picture will become blurry. I believe everyone has a deep understanding of this.
The price of professional infrared lens is several times that of ordinary lens. Why? Because the infrared lens is clear during the day and night, the effect is good and naturally expensive. The reason for the big difference in performance and price:
Since glass has different refractive indices for light of different wavelengths, the position of the focus point will be different. At present, ordinary lenses on the market can gather light with a wavelength difference of about 250nm on the same plane, that is, light in the range of 430nm~650nm or 650nm~900nm can be successfully focused, showing a clear image. This is why the normal lens is adjusted sharply during the day and the night vision is blurred, or the night vision is adjusted clearly and blurred during the day.