How to take infrared photos with f707

Speaking of infrared photography, the first reaction of friends who have played with cameras a few years ago is F707, which is equipped with Sony's unique NightShot mode and can shoot infrared images of objects. In addition to giving people a brand-new visual experience, it also leads to a sensitive topic, that is, "perspective". For this perspective function, the 58mm infrared filter suitable for F707 has never been jumped to Luoyang Paper.

The secret of F707 infrared photography is hidden in the night shooting mode, but the working principle of the night shooting mode should start with the ubiquitous light in our lives. Light is a kind of radiation that can be observed by human eyes. Experiments show that light is electromagnetic radiation, and the wavelength range of this part of electromagnetic wave is about 0.77 micron of red light to 0.39 micron of purple light. Electromagnetic waves with a wavelength of more than 0.77 micron to about 1000 micron are called "infrared rays". Below 0.39 micron to about 0.04 micron is called "ultraviolet". Infrared and ultraviolet rays can't cause vision, but the existence of this luminous object can be measured and detected by optical instruments or photography. Therefore, the concept of light in optics can also be extended to infrared and ultraviolet fields. Even X-rays are considered as light, and the spectrum of visible light is only a part of the electromagnetic spectrum.

In digital cameras, CCD/CMOS, as a photosensitive device, has a wider light sensitivity than human eyes and can basically cover the range from infrared to ultraviolet. Therefore, in order to prevent infrared rays and ultraviolet rays from interfering with imaging, the lens coating of digital cameras generally has the ability to filter ultraviolet rays (UV mirrors also have this function), while the low-pass filter placed in front of CCD/CMOS has the ability to filter infrared rays.

The secret of F707' s perspective ability is also related to the low-pass filter. In the night shooting mode, the camera will remove the low-pass filter in front of the CCD and directly use infrared to view and image. Infrared rays can penetrate some fine chemical fiber materials. By installing an infrared filter lens in front of the lens, you can see some places that are difficult to see under visible light conditions.

Although most DC can't actively remove the low-pass filter in a certain mode like F707, it still retains some ability to perceive infrared rays. After all, it is impossible for a low-pass filter to accurately filter out all infrared rays, and these fish that slip through the net are the basis for our amateur players to play infrared photography.

The easiest way to test whether the camera has infrared sensitivity is the TV remote control at home. Remote controllers usually use infrared diodes to send codes. When you press the remote control, people can't see the light from the diode in front of the remote control, but the camera can. Just take some pictures of it.

Make sure the camera has infrared sensitivity, so you need to prepare an infrared lens. In addition, it should be noted that the camera can't focus automatically after installing the infrared filter, so it needs to focus manually, so it is best to fix the position with a tripod first, and then install the infrared filter after focusing properly. This operation requires a camera with AFL focus lock or a remote control with focus lock function, otherwise it is still manual.