What is the camera's leather cavity used for?

I’m not sure what you mean by Pi Qiang here.

Generally, the bellows used for SLR cameras should be used for macro photography.

I use a Nikon camera with a PB-6 leather chamber.

The usage is to connect the lens to the leather cavity, and then connect the leather cavity to the camera body. This allows you to shoot closer objects and get clearer images.

For example, if you mount a 20mm lens on the PB-6 through the BR-2A and then mount it on the camera, you can achieve a magnification of 11 times, and you can take pictures of the compound eyes of dragonflies.

Currently in the Japanese market, second-hand PB-6 costs about one thousand yuan.

In order to ensure that the axis is consistent, PB-6 has tracks. I have never used the tilt-shift leather chamber you mentioned.

Theoretically, the leather cavity can be connected to various lenses. I usually use fixed focus heads such as headers.