how were Oppenheimer and Groves able to stand at ground zero right after the first atom bomb exploded without getting radiation poisoning?

Question

Speaking specifically to this picture

https://www.atomicarchive.com/history/trinity/afterwards.html

In: 685

Answer 1

If the radiation had been strong enough to kill, then the film in the camera would likely have been exposed and the picture could not have been taken in the first place.