| 摘要 |
<p>A lens device for a photographic printer to enable it to print same size prints from full-frame and half-frame images intermixed in an elongate strip of spliced film strips. If the lens device is one of two and is dedicated to printing half-frame images, the lens device rotates the image through 90° without affecting the inversion and reversion needed in a printer lens. The device includes a pechan prism in each of the air spaces between the lens elements and the object and image planes, respectively. There is a relative angular displacement of 45° between the prisms. The device enlarges the image more than the other lens, which is dedicated to full-frame images, so that images printed by both lenses have the same size. If the lens device is the only lens in the printer, then it is a zoom lens, so that images from both full and half-frame may be the same size, and the relative angular displacement between the prisms is variable so that both full and half-frame may be printed on the paper web with the same orientation on the web.</p> |
