1. A method comprising: capturing an image as a captured image at a capture exposure value; changing the exposure of a current iteration of the image by at least a fraction of an exposure value; capturing a changed exposure image at the changed exposure value; ascertaining a difference between an exposure data metric of the current iteration of the changed exposure image and an exposure data metric of a previous iteration of the image; comparing the difference between the exposure data metric of the current iteration of the changed exposure image and the exposure data metric of the previous iteration of the image to a difference threshold; and repeating changing the exposure value, capturing the changed exposure image, ascertaining the difference, and comparing the difference when the difference between the exposure data metric of the current iteration of the changed exposure image and the exposure data metric of the previous iteration of the image exceeds the difference threshold.