For this one have dropped the 51 point 3D Nikon 300 parameter and reverted to OS (stabilization) and standard 8 point central focus. This gives much better focus and a high level of keepers.
Hand held from about 15 meters in good morning light. The Sigma is proving to be an effective lens up to 20 meters or so. Quite sufficient for my hobbyist garden work in good light. Have not tested it beyond.