Predictive focus tracking apparatus and methods

An imaging system may include a sample stage comprising a surface to support a sample container, the sample container including a sample having a plurality of sample locations; an optical stage to image the sample at the plurality of sample locations; one or more actuators physically coupled to at least one of the sample stage and the optical stage to move the sample stage relative to the optical stage to focus the optical stage onto a current sample location of the plurality of sample locations; a first light source to illuminate the current sample location; a second light source to project a pair of spots on a next sample location of the plurality of sample locations; and a controller to determine, based on an image of the pair of spots projected on the next sample location, a focus setting for the next sample location.