The focus-tool accessory, allows any FLIR TAU lens which cannot be focused by hand to be focused by engaging the appropriate slots on the lens barrel such that it can be rotated inside the lens flange. (The focus tool has been properly sized such that no vignetting results when itengages the slots on the lens barrel.) Note that lens configurations with focal length.
Note that these lenses are intended to furnish a sealed rating of IP-67 at infinity focus. Lens focus is set with a collimator at the factory, and changing focus may compromise the o-ring seal in the WFOV lenses, and result in loss of optimum focus. Warranty claims may be voided in cases where refocusing creates repair issues with the lens, lens holder, or IP-67 rating.