This, of course, is a wonderful and emotive portrait. My thoughts are to be aware of the negative space. This shot has maybe a little too much at the top of the photo, and as the arm sort of leads you that way, you don't want too much space to get lost in.
What I like is that you realize that a portrait doesn't *have* to focus on the face! You've focused on the area that is relevant to you, and show a part of the baby that sometimes gets missed, and will be wonderful to look back on in the years to come.
Another thought is to maybe put this shot in a landscape orientation as well.. That would help build the relationship to the proneness of the body, and give the hand a way to become more a focus, being perpendicular to the orientation of the photo.
Great control over technicals IMO.. and a shot to be proud of. |