Methods and systems for tracking focus of an adjustable variable focus lens-based imaging system are disclosed. An example method includes identifying an initial focus position of an adjustable variable focus lens assembly and determining focusing parameters corresponding to that focus position. The focusing parameters are compared to a lens behavior model and a new, compensated focus position of the lens assembly is determined correcting for changes in lens assembly performance. A small window focusing sweep range, between forward and aft positions, may also be adjusted based on the lens behavior model to better identify the compensated focus position.