An optical system for a remote video inspection device including an elongated probe for inspection of target objects, comprising: an imager located distally within the probe, wherein the imager receives an image of the target object; a focus lens group located within the probe, the focus lens group comprising a variable aperture and at least one focus lens; a zoom lens group located within the probe, the zoom lens group comprising at least one zoom lens, wherein the movement of the zoom lens group in relation to the imager changes the magnification of the image; a tip lens located further from the imager than the focus lens group and the zoom lens group, wherein the distance between the tip lens and the imager is fixed; wherein a first movement of the focus lens group proportional to the movement of the zoom lens group provides an initial image focus, and a second movement of the focus lens group independent of the movement of the zoom lens provides a final image focus and proportional changes to the size of the variable aperture.