1. In a machine vision inspection system, a method for focusing to provide an inspection image, the method comprising: during a run mode of the machine vision inspection system, automatically approximately focusing an inspection image using a set of operations comprising: acquiring a first image of a current region of interest including a feature to be inspected and determining a first image focus value that is indicative of a first focus in the current region of interest; accessing previously learned representative feature-specific focus curve data and focus threshold value data corresponding to the current region of interest; and evaluating the first image focus value to determine if the first focus indicated by the first image focus value is less focused than a threshold focus indicated by a focus threshold value and, when the first focus is less focused than the threshold focus, performing a subset of operations comprising: moving a focusing element that is one of (a) the feature to be inspected and (b) a focus determining optical element, along a primary adjustment direction for an estimated primary adjustment distance, wherein the primary adjustment distance is estimated based on the representative feature-specific focus curve data and the first image focus value; acquiring a second image of the current region of interest after moving the focusing element the estimated primary adjustment distance, and determining a second image focus value that is indicative of a second focus in the region of interest in the second image; and evaluating the second image focus value to determine if the second focus is less focused than a focus indicated by a previously determined focus value parameter and, when the second focus is less focused than the focus indicated by the previously determined focus value parameter, moving the focusing element along a secondary adjustment direction that is opposite to the primary adjustment direction for an estimated secondary adjustment distance that is an estimated distance to a best focus position based at least in part on one of (c) the primary adjustment distance and (d) the representative feature-specific focus curve data.