1. An apparatus for electronically capturing images, comprising: (a) an imaging device; (b) a focus control element coupled to the imaging device; (c) a processor coupled to the imaging device and the focus control element; (d) memory coupled to the computer processor and configured for retaining images captured from the imaging device and for retaining programming executable by the computer processor; and (e) programming executable by the computer processor for carrying out steps comprising: capturing a plurality of object images; calculating sets of matching errors and blur difference estimations relating to the images; calculating a confidence indicator as a function of either the matching errors or blur difference estimations; and automatically adjusting the focus control element in response to said confidence indicator exceeding a threshold value; wherein the confidence indicator is calculated according to the equation: E = E 1 - E 2 k E · ( E 1 + E 2 ) + 1 where E is the confidence indicator, E 1 and E 2 are estimations of error for first and second directions, and k E is a non-negative constant.