A zooming microscope is a microscope that has a continuously variable magnification, typically over a range of about 4x to 50x or more. This is achieved by moving the objective lenses closer to or further away from the sample being observed. Zooming microscopes are also known as varifocal microscopes. They are useful because they allow the user to easily adjust the magnification of the microscope without having to change the objective lenses, which can be time-consuming and inconvenient. They are often used in educational settings, where students may need to observe a variety of samples at different magnifications. They are also used in research and industrial settings where the ability to quickly adjust the magnification can be useful.