A capturing device for a vehicle system, the capturing device comprising: an image sensor mounted on the rear of the vehicle, for performing photoelectric conversion on light from a subject and generating an image signal; a storage unit having a first region (132α) for storing first image data and a second region (132β) for storing second image data; a timing adjusting unit configured to adjust a timing at which the image signal is read out from the image sensor to write the image signal in the storage unit, and a timing at which the image signal is read out from the storage unit; an image conversion processing unit for performing a predetermined process on the image from the image signal read out from the image sensor, the image conversion processing unit being configured to cut out a specified region, specified by a set value, from the image represented by the image signal and to alternately write a first image signal in the first region (132α) of said storage unit and to write a second image signal in the second region of the storage unit, one of the first and second image signals corresponding to a full image from a first frame period of the image signal input from the image sensor and the other of the first and second image signals corresponding to a partial image which corresponds to said specified region of the full image in a different frame period from said first frame period, by adjusting the timings and thus changing frames for writing the image signal for each frame; an output unit configured to convert the first and second image signals read out from the first and second regions (132α,132β) at continuous scanning timings into an image signal in a predetermined format and to output the converted image signal; and a display control unit configured to display a window of which a size and position are changed in response to an operation input from a user on a display unit for displaying the image from the image signal output from the output unit, wherein the control unit is configured to generate the set value on the basis of the size and position of the window; and further comprising an image quality adjusting unit configured to perform control of an operation of the image sensor and to perform different controls for adjusting image quality of the images from the first and second image signals written in the first and second regions on the first and second image signals at a timing at which the image signal is loaded from the image sensor for each frame. an image sensor mounted on the rear of the vehicle, for performing photoelectric conversion on light from a subject and generating an image signal; a storage unit having a first region (132α) for storing first image data and a second region (132β) for storing second image data; a timing adjusting unit configured to adjust a timing at which the image signal is read out from the image sensor to write the image signal in the storage unit, and a timing at which the image signal is read out from the storage unit; an image conversion processing unit for performing a predetermined process on the image from the image signal read out from the image sensor, the image conversion processing unit being configured to cut out a specified region, specified by a set value, from the image represented by the image signal and to alternately write a first image signal in the first region (132α) of said storage unit and to write a second image signal in the second region of the storage unit, one of the first and second image signals corresponding to a full image from a first frame period of the image signal input from the image sensor and the other of the first and second image signals corresponding to a partial image which corresponds to said specified region of the full image in a different frame period from said first frame period, by adjusting the timings and thus changing frames for writing the image signal for each frame; an output unit configured to convert the first and second image signals read out from the first and second regions (132α,132β) at continuous scanning timings into an image signal in a predetermined format and to output the converted image signal; and a display control unit configured to display a window of which a size and position are changed in response to an operation input from a user on a display unit for displaying the image from the image signal output from the output unit, wherein the control unit is configured to generate the set value on the basis of the size and position of the window; and further comprising an image quality adjusting unit configured to perform control of an operation of the image sensor and to perform different controls for adjusting image quality of the images from the first and second image signals written in the first and second regions on the first and second image signals at a timing at which the image signal is loaded from the image sensor for each frame.