direct-optical viewfinder

A direct-optical viewfinder in photography is a camera component that allows the photographer to see the exact area of the subject that will be captured in the photograph. Unlike reflex viewfinders, which use mirrors and lenses to project the image onto a screen, a direct-optical viewfinder, often called a bright-line viewfinder, functions like an inverted Galilean telescope. This system projects a rectangle of light that outlines the intended frame, providing an image that is neither inverted nor reversed. A common issue with direct-optical viewfinders is parallax error, which occurs because the viewfinder and the camera lens are not in the exact same position. This error is more noticeable with close subjects and can result in parts of the subject appearing cut off in the final image, even if they were fully visible in the viewfinder.12