Infrared photography skills

The so-called infrared photography is to let the camera only let infrared light pass through the filter to produce images different from those seen by the naked eye. Infrared photography is mostly used to shoot landscapes, and white leaves and unusually blue sky are the most common themes. Infrared photography will make everyday scenery unique. Let's appreciate the unique charm of infrared photography and understand its shooting method.

Infrared photography is different from what the naked eye sees, mainly because people can't see infrared rays. The light that human eyes can see is only a small part of the spectrum (visible light), and its wavelength is in the range of 400-700nm. The wavelength of infrared light is 700 nm- 1 mm (strictly speaking, the infrared photos you usually see belong to "semi-infrared" 720-750nm, because pure infrared photography has only black and white, and there are no other colors. Although people can't see infrared rays, the camera's sensors can record infrared rays, so in order to keep the recorded images the same as what we see with the naked eye, most cameras have built-in filters to automatically filter out infrared rays. So if you want to "see" infrared, you have to start with the filter.

Method 1: Add an external filter.

This is a simple and cheap method! Buy a 720nm infrared filter and put it in front of the lens. The cost is very low, and the disadvantage is that it is more laborious to shoot. After installing the filter, the lens becomes completely black, because the filter blocks all visible light and only allows infrared rays with a wavelength of 720nm to pass through, so you can't see anything and can't focus. Before each shot, you should take off the filter, focus the picture, and then put it back in the filter to shoot. On the other hand, only a small amount of infrared rays can enter the camera because the built-in filter (that is, the one that blocks infrared rays) is still there. In order to achieve obvious results, it takes a long exposure time, generally more than 15-20 seconds, and it needs to be shot with a tripod; In other words, the subject matter of shooting is limited, so this method can only be applied to shooting still life and scenery in most cases.

Method 2: refit the camera internally.

Compared with purchasing external filters, this method is more troublesome and requires a certain knowledge of camera structure to disassemble internal parts. The cost is also higher, because you can't take normal photos after modification. The specific method is to disassemble the camera, remove the low-pass filter in front of the photosensitive element and replace it with an infrared filter with the same thickness. The influence of refitting the camera on the shutter speed is not particularly great, so you can also shoot by hand or directly through the viewfinder.

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