The present disclosure relates generally to cell phones and cameras, and to shadow analysis in imagery captured by such cell phones and cameras. One claim recites a method comprising: identifying a shadow cast by a cell phone on a subject being imaged by a camera included in the cell phone; and using a programmed electronic processor, determining proximity to the subject based on an analysis of the shadow. Another claim recites a mobile phone comprising: a camera for capturing images and video; memory; and one or more processors programmed for: identifying a shadow cast by a cell phone on a subject being imaged by said imager; and determining proximity to the subject based on an analysis of the shadow. Of course, other claims and combinations are provided too.