Ask permission before taking pictures, and steer clear of pictures that "exoticize" or patronize the other.
Norms governing photography vary enormously around the world. In most of Europe, you can take pictures of just about anything with no problem. In other places, you will be expected to pay to take someone's picture. In other places, folks think that the camera captures their spirit, and they don't like it. In still others, there are religious objections.
In some (indeed, many) countries, you cannot/should not photograph official buildings, particularly ones of military significance. This would include airports, police stations, town halls, etc.
The rule is basically simple: if in doubt, ask. You may think you have the right to take whatever pictures you want, but other people see it differently.
Taking Photos in Other Countries and Cultures
(from Pacific Lutheran University)
1) REFLECT ON WHY YOU'RE TAKING A PHOTO: Is it because you want to remember something, show your family your hotel, create a record of a place or people, or because taking pictures just seems natural? Many people take photos when they travel because they need to feel busy or to put something between them and new surroundings. Take time to simply enjoy the experience and realize different types of photos require time and care to take.
2) BE INTERACTIVE: Try to take more interactive photos compared to objective ones. Try to always ask permission when taking pictures of people. Getting peoples' names and stories as well as their photo can be a meaningful experience. It also will give more meaning to your photo when you bring it back and helps avoid the objectification of people that can commonly happen in photos of unfamiliar places, especially ones we think of as more "exotic".
3) WHAT'S IN AND WHAT'S OUT?: Think about what you want to include in your pictures - and then look at what you might be leaving out. Are you ignoring part of a person's life or the story of a town because you don't think it is "picturesque enough"? Realize that no photo is going to capture the reality of any place you visit, so think about how you can strive to show many different aspects of a place or culture, not just the tourist spots or well-known parts of a culture that everyone takes photos of.
4) CONSIDER AND RESPECT HISTORICAL AND CULTURAL ASPECTS AND LAWS: Most people know to ask permission to take photos in sacred or religious sites, but many countries also have laws against taking photos of government buildings and more. And even if there is no law against taking a photo, be respectful of the culture - a city, village, or landscape is not there for you to consumer through your camera, but is part of the lives of those in your host country.
5) SHOW PEOPLE YOUR CAMERA AND PHOTOS: Digital cameras are great to interact with people you might take photos of. Kids especially like to see themselves on the camera screens. Letting people you meet play with your camera a little can be a hit too if you are spending a good amount of time with someone.
6) PHOTO EXCHANGE: When possible, try to find a way to give a copy of the photo to the people you take pictures of. Getting their address and sending them a photo is sometimes and option or if you are meeting people through an organization or traveling with a company, think about sending them the photos to distribute. You could also bring photos of yourself or your family to give out to people when you take their photo or meet them.
7) THINK ABOUT YOUR CAPTIONS: When you present a photo, be intentional about captions and how you choose to label and title a photo. When possible, give names and details and a greater context to the photo and be careful about what you are and are not comparing the people or place to. The photos should be part of a story you can share with people once you return home.