The most recent phones are quite capable of being viewed in sunlight.Phone displays are tough in general. I've not found one that can really punch through the ambient light of a bright day. In combination with punching up the screen brightness briefly, I've found that shading with the palm of one hand while controlling with the other works for me.
David.... thank you for your comment which is most appreciated. I am truly amazed at what the iPhone is capable of producing and I am using it quite often these days. It works best for me in a close up/moody design situation.Ben - Those are exceptional images!