Since the development of the first light microscope over 400 years ago, the technology has continuously evolved and established itself as a powerful tool, especially in biology, diagnostics and point-of-care (PoC) applications. The miniaturization of mass-produced actuators and sensors enables the use of technically extremely complex functions in smartphones at a very low price. They can be used to implement modern microscopy methods for use in places where access to such techniques is often very limited. In this review, we show how easy it is to integrate a smartphone into the everyday microscopy-imaging routines of biology research. Such devices have also been used to identify diseases directly at the patient. Furthermore, we demonstrate how constantly increasing computing power in combination with the steadily improving imaging quality of cameras of handheld devices enables the realization of new biomedical imaging methods, which together with commercially available and 3D-printed components make current research available to a broad mass. Examples are smartphone-based super-resolution microscopy (SRM) or task-specific single-board computerbased devices, which can analyze plankton in sea water.