A focusing system within an imaging device (200, 301), comprising: a first lens (101, 210, 304); a memory component configured to store lens parameters of the first lens (101, 210, 304) and regions of focus corresponding to the lens parameters, wherein the lens parameters include a focal length and an aperture of the first lens (101, 210, 304) when focused at a particular focal distance; and a processor coupled to the memory, a range finding system, and the first lens (101, 210, 304), the range finding system configured to send to the processor information indicative of a distance from the imaging device to a target object (102, 302); and the processor configured to focus the first lens (101, 210, 304) on the target object at a first instance of time, obtain lens parameters of the first lens (101, 210, 304) when focused on the target object (102, 302) at the first instance of time, determine a region of focus of the first lens (101, 210, 304) based on the distance at the first instance of time and lens parameters at the first instance of time, wherein the region of focus is a region along the optical axis of the first lens (101, 210, 304) in a focal direction; receive, from the range finding system, information indicative of distances from the imaging device (200, 301) to the target object (102, 302) over a period of time, the first instance of time beginning the period of time, and at a second instance of time, trigger the first lens (101, 210, 304) to re-focus on the target object (102, 302) if the distance to the target object (102, 302) indicates the target object (102, 302) is outside of the region of focus, the period of time ending at the second instance of time. a first lens (101, 210, 304); a memory component configured to store lens parameters of the first lens (101, 210, 304) and regions of focus corresponding to the lens parameters, wherein the lens parameters include a focal length and an aperture of the first lens (101, 210, 304) when focused at a particular focal distance; and a processor coupled to the memory, a range finding system, and the first lens (101, 210, 304), the range finding system configured to send to the processor information indicative of a distance from the imaging device to a target object (102, 302); and the processor configured to focus the first lens (101, 210, 304) on the target object at a first instance of time, obtain lens parameters of the first lens (101, 210, 304) when focused on the target object (102, 302) at the first instance of time, determine a region of focus of the first lens (101, 210, 304) based on the distance at the first instance of time and lens parameters at the first instance of time, wherein the region of focus is a region along the optical axis of the first lens (101, 210, 304) in a focal direction; receive, from the range finding system, information indicative of distances from the imaging device (200, 301) to the target object (102, 302) over a period of time, the first instance of time beginning the period of time, and at a second instance of time, trigger the first lens (101, 210, 304) to re-focus on the target object (102, 302) if the distance to the target object (102, 302) indicates the target object (102, 302) is outside of the region of focus, the period of time ending at the second instance of time.