For varifocal lenses, first select the appropriate focal length using the zoom ring on the lens and identify the target. Next, open the iris ring of the lens completely so the maximum amount of light hits the sensor. Looking in the end of the lens, you will notice the iris shifts from a pinpoint to a much wider opening when this ring is adjusted. Finally, use the focus ring to focus in the sweet spot of the camera's image. While performing this process, creating an ROI within AV100 will help with performing fine tune focus adjustments. Once the best focus is achieved, lock the set screw of the focus ring in place along with the zoom ring. Finally, slightly closing the iris ring of the lens will help increase depth of field within the image. The end result should be a well focused image.
For fixed focal length lenses, ensure the aperture/iris ring (if available) of the lens is open completely and then use the focus ring to focus the image. Once proper focus is achieved, the iris of the lens can be closed to help increase depth of field within the image. Not all fixed focal length lenses have an aperture/iris ring available.
Lenses vary in the location of these rings but should be labeled to help assist with adjustment.