This is a specialised type of lens which can be tilted relative to the camera body. This changes the plane of sharp focus and can be used to extend or contract the available depth of field. It’s often used to make real-world subjects look like miniature models by tricking the eye with shallow depth of field, or to extend the depth of field for still life or product photography. The shift adjustment is different, shifting the lens parallel to the camera, most often to get tall buildings into the frame in architectural shots without having to tilt the camera. These are often called perspective correction lenses. Tilt effects can also be simulated digitally using tools which leave a central strip of the photo in sharp focus but progressively blur the rest of the image towards the edges. It’s also possible to apply perspective correction in software to remove converging verticals (keystoning) in pictures of buildings.