Dude, been to Sri Lanka few years ago. What a beautiful place! Galle and Kandy are amazing. I won't be able to give you specific places to visit but:
1. In Galle, stay within the old city walls; really picturesque and with plenty of weirdness to photograph. Walk to the seaside to see young people jumping off city walls and lovers hiding behind umbrellas... If you walk around the town at night you will most likely stumble upon the market they sometimes have, and while it's small, it's quite interesting to see. Galle is great for slow, peaceful moves around town. It's not too noisy. Be sure to find Fazaad Badurden's cafe (for the love of god, I can't remember the name of the place - ask anyone) and have a breakfast.
2. I've actually been to Galle during the New Year's of 2010 - and if you are lucky, you might encounter the peculiar live market/show/outdoor celebration they're putting outside the city walls. It's fantastic, but it's mostly at night so not sure if it rocks your photographic boat. It did rock mine 😀 Plenty of live music and food. And everyone that lives in Galle comes. Craziness. In all beautiful ways.
3. Colombo - didn't like it. Noisy, dirty, but not in a nice, Saigon-like way. I found it sticky and obtrusive, and back then there was plenty of military activity around. It wasn't nice. Might be better now.
4. Kandy is wonderful. Wonder around the temple area, and if you spend some time in neighbouring streets you will walk into many tiny shops and markets. Make sure you go to the central market that's near to bus station. You'll find it by the smell, since they sell lots of fish that travelled for a while. Be prepared for no other tourist in sight so move quickly - Bresson mode on! 😀 Real Asian market experience doesn't get any better than that.
You will love it. Sri Lanka is a great place. One of the best trips I've had. Enjoy!
