Abstract: A method and system are provided for controlling focus dynamically of a sample imager. The method comprises scanning a sample with an optical assembly that apportions the sample into regions based on a scan pattern. The optical assembly has a focal setting with respect to the sample. The method further comprises shifting the focal setting of the optical assembly during scanning of the sample, and detecting one or more images representative of one of the regions from the sample. The one or more images have associated degrees of focus corresponding to the focal setting of the optical assembly. The method analyzes the image(s) to obtain a focus score or scores corresponding thereto, where the focus scores represent a degree to which the optical assembly was in focus when detecting the images. The method adjusts the focus setting based on the focus score(s).