1. An image capturing device comprising: an image capturing unit configured to perform image capturing by forming an image of a subject with an optical system; an operation unit configured to set an image capturing parameter including at least one of a focus position, an f-stop, and a zoom magnification in performing the image capturing with the image capturing unit; an acquiring unit configured to acquire, by using the image capturing parameter set by the operation unit, a plurality of image data captured by the image capturing unit; a setting unit configured to set, based on an input from a user operating the operation unit after the plurality of image data are captured, a combination parameter used for combining the plurality of image data acquired by the acquiring unit; and a combining unit configured to combine the plurality of image data by using the combination parameter set by the setting unit to generate combined image data.