Abstract: A follow focus apparatus for adjusting the focus of a camera lens includes a circular gear ring having opposed inner and outer surfaces and defining an open interior area, the inner surface having a planar configuration. A plurality of spaced apart teeth are situated on the outer surface of the gear ring. The apparatus includes a sizing member selectively received in a cutout area defined by an inner surface of the gear ring so as to decrease an inner diameter by a predetermined amount. The apparatus includes a sizing ring having a configuration received in the gear ring interior area, the sizing ring being configured to decrease the inner diameter of the gear ring by a predetermined amount. The sizing ring includes an outwardly extending projection configured to nest in corresponding notches defined by the gear ring inner surface so as to secure the sizing ring in the gear.