In my more courageous days, I would travel to Philly and do candid flash photography at night. It was nerve-racking and fun. I survived and got some good results. I never got into an argument or fight. Given the increasing violence of the last few years, I will limit my photographic activities to daylight hours.
For my candid flash photo’s I set my camera to shutter speed mode at 1/400 to ensure a crisp image. With the flash on the ISO went to 400 which is perfectly acceptable for street photography. The aperture, in these situations, will always be wide. Since I’m shooting people, a 1.8 wide aperture will keep the focus on the subject and the backgrounds blurry.
This photo can found on flickr at https://www.flickr.com/photos/viewfromthestreet/14712502371