Welcome to the site, Joshua. First of all, you need to get your photo terms straight. This classic Avedon shot of Taylor has of course relatively high contrast, not low. Yes there are soft transitions, but the overall range from light to dark is great. And while her expression is soft, the lighting is quite hard (note the shadow under her nose).Originally Posted by Joshua Thomas
Note the catchlight in Taylor's eyes. Looks like a single light, possibly bounced into a medium umbrella. Its position is not too much higher than the subject's eye level (again note the nose shadow).
Avedon's lighting was usually very simple, as it is here. The impact of his images often was more the result of styling and the expressions of his subject.
Hope that helps...