An analyzer apparatus and method of use thereof is described to dynamically irradiate a sample with incident light where the incident light is varied in time in terms of any of: position, radial position relative to a point of the skin of a subject, solid angle, incident angle, depth of focus, energy, and/or intensity. For example, the incident light is varied in radial position as a function of time relative to one or more of a sample site, a point on skin of the subject, a detection optic, and/or a sample volume observed by a detection system. The radially varied incident light is used to enhance and/or vary light probing the epidermis, the dermis, and/or the subcutaneous fat of the subject or of a group of subjects.