Ness started off as a very charismatic, enthusiastic, and overall a good samaritan until he meets Phyllis. Upon seeing Phyllis, he is instantly captured by her looks. In the first shot of his expression of Phyllis, it is obvious Neff is lusting for Phyllis. The downward medium shot shows just enough of Neff to understand his facial expressions while demeaning him, almost as if he were a pet dog to Phyllis and glad to see his owner. The lighting on his entire body suggests there is a purity to Neff, which is entirely true before he gets infected by Phyllis.
After killing Mr. Dietrichson, Ness becomes very paranoid of what can happen, and ultimately loses his affection towards Phyllis. In this scene, his entire face is covered by darkness, without the smirk he had towards Phyllis when he first saw her. The lighting is very important because unlike the previous shot, Ness is completely dark, which could mean he's lost his purity. The medium length shot is important because it shows both Ness and Phyllis. This is important because it shows the lack of Ness' interest in Phyllis, maybe showing his realization of what he's done.
I couldn't find the last picture, but I was looking for a picture of Ness after he got shot, while holding Phyllis. I believe this scene was important because this scene was done in completely pitch black, maybe signifying Ness has completely fallen, unable to return to his pure life from before. This is the final part of his transformation, where it shows Ness transforming from a pure man, to a murderer and adulterous.
