1. An image capture device, comprising: an image pickup module, arranged for capturing a plurality of temporary images from a plurality of visual angles of a scene in advance by using a plurality of scanning focal length values; and a processing module, arranged for obtaining a temporary focal length value by weighing each of the scanning focal length values of the plurality of temporary images of each of the visual angles, and obtaining a weighting focal length value according to a function and the temporary focal length value, to control the image pickup module to perform a panorama image capturing process according to the weighting focal length value, wherein the function is a summation of each products of the temporary focal length value corresponding to each of the visual angles multiplied by a ratio, which is a quantity of the plurality of temporary images corresponding to the visual angles divided by the total quantity of the plurality of temporary images corresponding to each of the visual angles.