Flynn, a former actor, singer and Duke student, and Stone, a former logger, model, sailor and gold prospector, had no prior formal photographic training before arriving in Southeast Asia. Their appetite for risk and adventure put them in great situations to take photos established them as some of the most famous photographers of the war. It also brought about their demise.
Zalin Grant wrote a great piece discussing their lives and their disappearance available here.
Men's Vogue has a slideshow documenting Sean Flynn's.
It looks like Dana is carrying three German made 35mm Nikon F's with what I imagine to be a 50mm, an 85mm and a 135mm.
Before becoming a photojournalist, Sean Flynn followed his father's foot steps, Errol Flynn, and tried his hand at acting, staring in two B grade action movies.