Imaging device and automatic focus adjustment method

An imaging device comprising:

• an imaging section for forming a subject image using a photographing lens, and generating image data;
• a contrast detection section for detecting contrast values corresponding to contrast of the subject image, for every position of the photographing lens, based on the image data;
• a subject brightness detection section for detecting brightness evaluation values corresponding to subject brightness of the subject image for every position of the photographing lens, based on the image data;
• a correction section for correcting the contrast values depending on a brightness evaluation value for a corresponding position of the photographing lens and calculating corrected contrast values;
• and
• a focus detection section for detecting a focus position of the photographing lens based on the corrected contrast values that have been corrected by the correction section, wherein the correction section calculates a ratio relating to the brightness evaluation values as a correction coefficient, and corrects the contrast values using the correction coefficient, and wherein the correction section adjusts the correction coefficient according to the contrast values.