This presentation is part of the μLecture series about useful microscopy-related topics, organized by the Microscopy Service Centre, IEM CAS. It focuses on the fundamentals of geometrical optics, introducing the basic concepts and principles, including the refractive index and the laws of reflection and refraction of light. Building on these principles, it explains the properties of lenses and demonstrates how they can be applied to understand the function and design of a microscope. It also describes how to correctly set up Köhler illumination, which provides ideal and uniform illumination of the entire microscope field of view.
Barbora Hyklova (2026) studied this question.