Will you have access to a rental car and be able to drive around the island? What are you looking to shoot? I can't suggest too much around Honolulu itself, my visits have been more for landscape, and I haven't spent much time inside Honolulu itself. If you weren't originally planning on renting a car, I'd seriously consider it so you can explore the island. I've been able to get amazingly low prices on hotwire (below $10/day more than once)
Here's a list of things landscape-oriented things from the top of my head (some rather touristy, but...hey, you're a tourist!
- Diamond Head Crater (nice hike up to the top, overlook over the ocean and Honolulu)
- Hanauma Bay - lots of tourists, but still a nice spot, snorkeling if you like that.
- Lanai Lookout - Rocky outcropping on the SE side. Careful as you climb down and explore the water-carved rock.
- Makpuu Point - Nice hike up the eastern-most section; parking near there has a nice view looking north up the coast.
- Kualoa Ranch/Ka'a'awa Valley - This is valley is somewhat touristy, because you have to pay to get in on various tours. They've filmed movies and tv shows in this valley (Godzilla's footprints are still there, Lost, Hawaii 5O, etc.), but it's a beautiful valley. Google it, and you'll probably recognize it from something
- Byodo-In Temple - replica of a temple in Japan.
- Drive the Pali Highway, very scenic, and go up to the Pali Lookout. Great view overlooking Kailua Bay and some other little towns; also location of a famous battle.
Just driving up the windward side (eastern coast) of Oahu, and then down the north shore is fantastic, lots of places to stop and shoot/enjoy.
- On the North Shore, Kawela Bay is a nice, generally secluded small bay to relax at, semi-photogenic. But the short walk from the road to bay has a lot of banyan trees that are nice to shoot/explore. There's also a hiking trail to the right a lot of people don't know about, follows the coast and eventually leads to an old military bunker. Go even further and you'll reach Turtle Bay resort. (By the way, I'd suggest stopping at one of the shrimp trucks
- On the north shore, a lot of people drive from the Honolulu side to Waialua, and turn right/NE; I'd suggest exploring the NW direction if you have time. Near the Dillingham airfield are several beaches that aren't as crowded as the 'typical' ones are, and the nearby mountains are beautiful.
- Papailoa Beach on the North Shore - Nice long stretch of beach, rarely crowded, and I've almost always found lots of turtles here.
- On the leeward coast (west), Ko Olina resort has some nice (but man-made) lagoons and beaches; if you take a long drive up the west coast, you'll reach the Kaena Point park, which is pretty nice, not usually crowded. Nice lava tidepools and mountains, some areas with lots of shells and such encased in the lava rock.
I'm sure I missed some spots, haha! I can suggest more once I know what type of things you're looking for.