An image apparatus may be configured to calculate a depth of an object relative to the image apparatus. The image apparatus may include an image sensor that may capture a plurality of images of the object. Depth calculation may include calculating a binocular disparity using the plurality of images, measuring a local temperature value from at least one temperature sensor, correcting a focal length of at least a portion of the image apparatus according to the measured local temperature value, and calculating a depth of the object using the binocular disparity and the corrected focal length. The corrected focal length may be determined based on a focal length variation value. The focal length variation value may be determined based on performing contrast autofocus on one or more captured images and the local temperature value.