Photographic wide-angle lens with internal focusing

摘要

The lens has a focusing group that is provided with a single optical element having positive refractive power. The single optical element is moved between a front group (I) and aperture (A). The focus distance is varied from maximum value to minimum value by linear displacement of single optical element from a maximum object side to maximum image side in axial position. The single optical element of focusing group (II) is provided with aspherical surface (51,52) and image side end lens (9) of rear group (III) is formed as a positive aspherical meniscus lens.