The 38 to me looks much better here. To me 100 is much to flat. And low numbers are to distorted. I like the camera focal at 50. This works the best for me in a normal portrait. Below 35 is fine if you want to have that kind of distortion. The lower the number the closer to a wide-angle/fish-eye you get. As with higher numbers the flatter the scence becomes, things seem to be on the same plane, when you know they're not. But again different scences/renders will look better at different focal lenghts. Well my 2 cents on the camera matter ;-) James