| 摘要 |
<p>A camera lens, for a simple Land camera consists of a positive meniscus with at least one aspherical refracting surface and a diaphragm in the vicinity of the coma free position of the meniscus. A second diaphragm (20) is located centrally between the first diaphragm (18) and the meniscus (16). The first diaphragm can be the aperture diaphragm and the second, a vignetting diaphragm. The aperture of the vignetting diaphragm can be slightly larger than that of the aperture diaphragm. The useful image area may extend over a half field angle of 26 deg. The lens may be fixed in either of two positions in the camera one for near objects and one for remote objects.</p> |
