Microscopy is the field of using microscopes to view objects. There are three well-known branches of microscopy, optical, electron and scanning probe microscopy.

The term resolution is the minimum distance between distinguishable objects in an image, although the term is loosely used by many users of microscopes and telescopes to describe resolving power.

Source: Wikipedia

Optical Microscopes

Optical or light microscopy involves passing visible light transmitted through or reflected from the sample through a single or multiple lenses to allow a magnified view of the sample.

Optical microscopes, through their use of visible wavelengths of light, are the simplest and hence most widely used type of microscope.

Typical magnification of a light microscope is up to 1500x with a theoretical resolution limit of around 0.2 micrometers or 200 nanometers.

Source: Wikipedia

Scanning Probe Microscopy

Scanning probe microscopy (SPM) is a branch of microscopy that forms images of surfaces using a physical probe that scans the specimen. An image of the surface is obtained by mechanically moving the probe in a raster scan of the specimen, line by line, and recording the probe-surface interaction as a function of position.

Examples of scanning probe microscopes are the atomic force microscope (AFM), the scanning tunneling microscope and the photonic force microscope.

Source:Wikipedia