Schneider 82mm Center Filter (#4) for 90mm f/5.6 and 120mm f/8 Super Angulon Lens

When working with ultra-wide-angle lenses, the fall off of illumination towards the corners is sometimes disturbing. For this reason, concentrically graduated Center Filters have been designed to compensate for this vignetting. These filters have a transparency which increases gradually from the center to the edges of the filter where it reaches full transparency. The transmission is independent from the wavelength of the visible spectrum. In order to avoid over exposure and with consideration of the exposure latitude of the film emulsions, we have not fully compensated for the vignetting of the lens.