Hello,
I live in Jakarta before working in Singapore.
Generally speaking of course Singapore is better in terms of safety.
My suggestion is:
- Since you're not a local, try to avoid going around alone. The best is to stick with your Indo friends.
- Try to avoid "dangerous" areas, especially at night. Tell your Indo friends that you don't want to take risk, so just visit safe places. Don't worry, there are a lot of great safe places to take pictures in Jakarta.
- Leave your expensive belongings / jeweleries / watch at hotel / home if you can.
- Good if you have a simple camera bag so it won't attract people's attention.
Shopping for camera / equipment in Jakarta is OK, as usual check for original warranty, and, if it's a second hand item, check the condition throughly.
PM me if you have anything else to ask. Have a pleasant trip =)