For decades, color slide film was the industry standard for commercial and editorial work, and the speed of the film was typically 64 or 100. It was standard practice for a portrait photographer to use a high-powered strobe to illuminate the subject. Today, a digital camera can produce clean images at high ISO settings and allows the photographer to forgo strobes and instead illuminate the subject using lower-power continuous light units.
[ Read More ](Originally posted by John Ricard)