1. A dynamic exposure adjusting method adapted for an electronic apparatus, comprising: capturing a plurality of preview images, a plurality of additional images, and a first image, wherein the additional images are not displayed in a display unit of the electronic apparatus; analyzing a luminance distribution condition of the first image; obtaining a long exposure time and a short exposure time according to the luminance distribution condition; retrieving at least one specific image corresponding to the long exposure time and the short exposure time from the additional images; and combining the first image and the at least one specific image as a processed image.