1. A method for operating a precision machine vision inspection system to determine an estimated best focus position that is at least approximately a best focus position usable for inspecting a region of interest of a workpiece, the precision machine vision inspection system comprising: an imaging system comprising: a camera having a pixel set corresponding to a full field of view of the camera, the camera operable to output the pixel values of at least one configuration of a reduced readout pixel set, the at least one configuration of a reduced readout pixel set corresponding to substantially less than the full field of view of the camera along at least one dimension of the field of view of the camera, and at least one lens configuration; a plurality of controllable motion axes including a focus axis, the focus axis including a focus axis position sensor; a control system portion; and a workpiece stage that carries the workpiece, wherein at least one of the workpiece stage and the imaging system is movable to provide relative motion with respect to the other at least along the focus axis, the method comprising: overlapping at least a majority of the region of interest and at least part of a reduced readout pixel set in the field of view of the camera; providing a motion, the motion including traversing a focus image range along the focus axis direction using continuous motion; inputting an auto focus image into the camera during the continuous motion, the auto focus image having a respective effective exposure time and exposure duration; outputting the pixel values of the reduced readout pixel set of the auto focus image to the control system portion during the continuous motion, the output pixel values of the auto focus image corresponding to substantially less than the full field of view of the camera along at least one dimension of the field of view of the camera; repeating the inputting and outputting steps to provide data for a plurality of reduced readout pixel sets corresponding to a plurality of auto focus images distributed along the focus image range; determining respective positions along the focus axis for at least some of the plurality of auto focus images; and determining an estimated best focus position that is at least approximately the best focus position usable for inspecting a region of interest of a workpiece based on at least some of the data for a plurality of reduced readout pixel sets and at least some of the respective positions along the focus axis for at least some of the plurality of auto focus images, wherein: the output pixel values of the outputting operation are output in a time that is substantially less than a time required for outputting the full pixel set corresponding to a full field of view of the camera; repeating the inputting and outputting steps is performed within a reduced time that is less than a standard time that corresponds to inputting an input image and outputting a pixel set corresponding to a full field of view of the camera; the plurality of auto focus images are distributed along the focus image range in a manner depending at least partially on the reduced time and the provided motion such that a maximum spacing along the focus axis between the respective positions of adjacent auto focus images is operational for determining the estimated best focus position that is at least approximately the best focus position to a desired level of accuracy; and the motion over at least a part of the focus image range is substantially faster than a fastest motion allowable in combination with the standard time in order to hypothetically produce adjacent auto focus images that are spaced apart along the focus axis direction by that maximum spacing between the respective positions of adjacent auto focus images.