I'm Mark Rosenstein. Contact me by email to mar at actwin.com. My handle here is pronounced "mar-ACT-win". I live in Cambridge, Massachusetts. If you're visiting the Boston area, message me if you'd like a local hiking companion.
I'm an avid scuba diver, fish geek and underwater photographer. I like to be able to name everything I see on a tropical reef. I'm working on a field guide to the reef fishes of Fiji. More recently I've become obsessed with bird watching, butterflies, and odonates. Interested in a little bit of everything else too, as I try to become a more rounded naturalist. Though I still do not know many plants.
This is all just a hobby; my day job is in computer programming.
Some have asked about my underwater photography. I use a Canon 7DmarkII dSLR inside an Aquatica housing, with dual Ikelite DS125 strobes. I shoot mostly with a 100mm macro lens, though also shoot wide with either a Sigma 17-70mm under an 8 inch dome or Tokina 10-17mm fisheye under a 4 inch dome.