Macro photography
Using what are called extension tubes. These are small inserts between the lens and the camera. They move the lens farther away from the camera, increasing reproduction ratio, decreasing depth of field. The main problem with that is that they cost light, usually cutting brightness by a factor between two and four. It may also be impossible to get a sharp view of the object photographed, if it is farther away. An extension tube where the distance can be changed continuously is called bellows.