Patent ID: 7969486
Filing Date: 2011-06-28
Classification: G02B

Abstract:
1. An image-capture apparatus comprising: a variable magnification lens; imaging means for converting an image taken by the variable magnification lens into an electrical image signal; and imaging control means, wherein; by referring to a conversion coordinate coefficient prepared in accordance with a variable magnification rate in advance by the variable magnification lens, the image control means moves a point on the image defined by the image signal formed by the imaging means to form a new image signal subjected to the coordinate conversion, and outputs the new image signal; in the variable magnification lens, in order from the object side, a first lens group having positive refractive power, a second lens group that has negative refractive power and performs a variable magnification action by shifting on an optical axis, a third lens group having positive refractive power, a fourth lens group that has negative refractive power, and in varying magnification from a wide angle end to a telephoto end, shifts to the image side once on the optical axis, and then shifts to the object side to correct fluctuation in image position caused by the variable magnification, and performs a focusing action, and a fifth lens group having positive refractive power are arrayed, and a T lens group formed of a positive lens group and a negative lens group located in order from the object side and is arranged between the fourth lens group and the fifth lens group in an insertable and detachable manner is included, in a first variable magnification form, the first lens group, the third lens group and the fifth lens group are fixed, the T lens group is withdrawn from an optical path to a position where the group does not disturb the shift of the fourth lens group, and mainly by shifting the second lens group in an optical axis direction, the magnification is varied, and by shifting the fourth lens group in the optical axis direction, the correction of the fluctuation in image position and the focusing are performed; and in a second variable magnification form, the second lens group is fixed to a position of the telephoto end in the first variable magnification form, the T lens group is inserted between the fourth lens group and the fifth lens group such that an optical axis of the T lens group is shared with other lens groups to make a focal distance longer than a focal distance at the telephoto end in the first variable magnification form, and the focusing is performed by the fourth lens group.