As noted in my PM reply to Rich earlier, but wanting to share with others viewing this thread, I can personally (and highly) recommend Sea And Land Eco Tours for scuba diving and much more in the Loreto area. The owners, Juve and Sara, are simply awesome and willing to work with you to help make your visit as great as possible. They can cater to small groups or even solo divers and cater to your diving style. As an avid u/w photographer, I sometimes plant myself at a strategic vantage point to capture images of specific sea life while at other times I blend into a large school of fish to capture images from within the school. Whether you are out with Juve or Sara, they just let you do your thing and watch from a little ways away. They are also open to taking time for surface encounters with whales, dolphins, Mobula Rays, etcetera if you are interested when the opportunity presents itself (like every time I was on the boat with them in 2013). You will find numerous reviews of Sea and Land Eco Tours on TripAdvisor, including my review. Take a look, they come highly recommended by many other divers as well.
~~Ray