You can buy our products through any authorized Schneider lens dealer for lenses, loupes, and related products. Even if they don't have what you want in stock, they can order it for you. Parts may be ordered directly from our service department. We don't know. You can look it up for yourself with our age of lenses chart.
Angle of view is the angle that the lens sees.
Angle of coverage is the angle that the film sees. Lenses are usually designed to project an image on the film plane that is larger than the film. Well . . . What actually happens is that when the lens is wide open, the center of the image is very bright and the corners of the image are VERY dark. As the lens is stopped down, uniformity of illumination improves and therefore the circle of usable illumination increases.