There are three different focus modes on board too: laser focus, depth focus and contrast focus as well as a dedicated depth measurement chip. (androidauthority.com)
Currently, different depth measurements are usually arrived at due to human error. (greatbluehole.com)
Smirnov, A., B.N. Holben, S.M. Sakerin, D.M. Kabanov, I. Slutsker, M. Chin, T.L. Diehl, L.A. Remer, R. Kahn, A. Ignatov, L. Liu, M. Mishchenko, T.F. Eck, T.L. Kucsera, D. Giles, and O.V. Kopelevich, 2006: Ship - based aerosol optical depth measurements in the Atlantic Ocean: Comparison with satellite retrievals and GOCART model. (pubs.giss.nasa.gov)