Patent ID: 7505211
Filing Date: 2009-03-17
Classification: G02B

Abstract:
1. Photographic wide angle zoom objective of the retrofocus type having a group of negative refractive power comprising four lens components and being a front group when seen from the object side, and having a rear group of positive refractive power including six lens components and facing an image plane, the distance between the rear group and the image plane being increased, and the distance between the front group and image plane being reduced, during an increase in the focal length, wherein the first two lens components have a negative refractive power when seen from the object side in the light direction, the third and fourth lens components are grouped into a cemented component with a positive total refractive power and the fifth lens component has a positive refractive power, the sixth and seventh lens components are grouped into a cemented component with a positive total refractive power, the eighth and ninth lens components are grouped into a cemented component with a negative total refractive power, and the tenth lens component has a positive refractive power.