How do darkfield microscopes create a dark field?

A darkfield microscope creates a dark field by utilizing a technique that involves directing light at an angle such that it misses the objective lens. In this setup, only the scattered light from the specimen enters the objective lens, while the background remains dark. This is achieved through a specialized condenser that focuses light on the specimen but does not allow direct light to reach the objective, making the background appear dark.

This principle allows for the observation of transparent or nearly invisible specimens, as the light that is scattered or diffracted by the specimen becomes visible against a dark background. The other methods mentioned do not effectively create the dark field needed for this type of microscopy. For instance, using filters or closing the diaphragm relates to different optical adjustments that do not specifically create the darkfield effect.