What are optical instruments primarily used for?

Optical instruments are primarily used to manipulate light. They employ the principles of optics to achieve various tasks, such as magnifying images, focusing light, or dispersing light into its constituent colors. By using lenses, mirrors, prisms, and other optical components, these instruments can modify the properties of light, allowing for applications in areas like photography, telescopes, microscopes, and even fiber optics.

The design and functionality of optical instruments hinge on controlling how light interacts with different materials, enabling us to observe distant objects more clearly or to see small details that would otherwise be invisible to the naked eye. Thus, the fundamental purpose of these instruments is centered around the manipulation of light, making the correct choice about their primary use clear.