Nyílásszög

Nyílásszög, meaning "aperture angle" in Hungarian, is a term primarily used in optics and photography. It refers to the angle subtended by the entrance pupil of an optical system at the focal point of the objective lens. In simpler terms, it describes how wide the "window" is that collects light from the scene being viewed or photographed.

A wider nyílásszög allows more light to enter the optical system. This is beneficial in low-light conditions, as it enables shorter exposure times or the use of lower ISO sensitivities, reducing noise. In photography, a larger aperture, often expressed as an f-number (e.g., f/1.8, f/2.8), directly corresponds to a wider nyílásszög. This also influences the depth of field, with wider apertures generally producing a shallower depth of field, isolating the subject from the background.

Conversely, a narrower nyílásszög restricts the amount of light entering the system. This is useful in bright conditions to avoid overexposure or to achieve a greater depth of field, ensuring more of the scene is in focus.

The concept of nyílásszög is fundamental to understanding how lenses gather light and how this impacts image quality and creative control in photography. It is a key characteristic that differentiates lenses and influences their suitability for various photographic applications.