The exact same thing happened to me a couple of years ago. The snatch was at 8:30am in the morning outside Notre Dame I am now much more cautious in Saigon as the level of crime has increased significantly in the last five years. This does not only affect tourists. I know many local people who have had laptops and iphone stolen out of their hand as they were making calls. Make sure your travel insurance can cover the FULL LOSS of your camera and lens. I now have 10k of cover after my previous insurance left me with a big loss .
Any recommendations on such travel insurance?