Like mjh said, you have to wedge into the rocks if you're a photographer, which means your knees will take a lot of abuse and your suit will get shredded by barnacles. If you have an old backup suit, this is the place to take it, as your new suit will never look the same. If the suit doesn't have decent knee protection built in, consider knee pads. Thick gloves are essential, and bring a backup pair in case the first pair gets shredded. Don't even think about a drysuit unless it's made of some very tough material. Personally I think they're uncomfortable to wear day in and day out on a liveaboard (I get a painful rash from the neck seal and shaving) and the water temps aren't really cold enough to warrant one, but shedding a wet wetsuit on a cold windy/rainy Galapagos morning can be a chilling experience if others are hogging the warm shower.
And watch out for sea urchins!
