| 摘要 |
PURPOSE:To attain a trimming photographing whose picture quality is good by altering the space between lenses at the time of photographing by trimming. CONSTITUTION:In case of executing the trimming photographing, a photographing lens is divided into plural parts in order to obtain a balanced astigmation in a trimming range and by altering the space between lenses of a lens group A and a lens group B, for example, the astigmation in a trimming area can be corrected. In order to prevent the movement of a focus, luminous flux projected from the lens group A is made into afocal light or one near to afocal light. By fixing the lens group B and moving the lens group A which is a nearly afocal optical system to an object side, the correction of astigmation in the trimming range is executed. Then a back focus and a focal distance are not altered so much. Since only one lens group A is moved, mechanical simplification can be attained and photographing having good picture quality can be attained.
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