Oddly though i live in the west, I've connected thru Newark several times to Carib dive destinations (direct flights)
So here's a couple:
Provo, Turks & Caicos which will mostly be boat diving. We did a live aboard there and one of the divers was a serious photographer - a couple times I just saw his legs under a coral head - he got some amazing macro - had the gear for it and knew how to use it.. Some NYC doctors on our boat flew in directly from one of the airports.
St. Thomas which has a few shore dives, is 1/2 hr. by ferry to St. John where there's a marine park and you can actually go via fast ferry to the BVI's for a lot of other shallow diving. My buddy is a photog and found plenty to shoot there.
Grand Csyman is another obvious choice - direct flights from NYC. Lots of reef so lots of photo ops. Cathy Church's photo school is located there at Sunset House.
The other obvious macro choice is Bonaire/Curacao. IDK the east coast flights as we go thru IAH. I'm pretty sure there is/was a direct flight to Bonaire on Saturdays.
Both islands are all small stuff, seahorses, nudis lots of eels and small invertebrates. Mostly shore diving so you save some money. Actually it's rare to see a shark on either island unless you go to specific dive sites.