Frame viewfinder (ikonometr) consists of two frames: short-and large format negatives, and they are separated from one another by a distance equal to focal length lens. Frame viewfinder gives the image in its actual size and is very convenient for viewing. Pass-through optical viewfinder consists of two rectangular lenses: the scattering and collecting (eyepiece), concluded in folding rim of the frame. Mirror optical viewfinder consists of two collecting lenses, one of which is less placed vertically and a second, larger size – horizontally at the top of the viewfinder; between them at an angle of 45 degrees to both lenses reinforced mirror, reflecting upward rays passed through the smaller lens. As a result, great lens forms a mirror-reversed image of your subject. Let's try to guess where the name came slr cameras.
Electronic viewfinder displays the image photographed by the camera lens. Electronic viewfinder – this lcd – the screen size is so important, is not it? rf cameras. Rangefinder – the best way the tangent the camera focus. Ranging called Devices designed to determine the distance from the observer to the observed object. The use of rangefinders in photographic practice borrowed from the artillery units range finders. Operating principle range finder based on the fact that if you look at one and the same object from two different points A and B, separated from one another at a distance, and so that the angle A must was a direct, depending on the distance from point A to observed object, the angle B will change.