When is it safe hand hold a camera? Camera movement is a major cause of blur in images. Our friends at the Nikon magazine N-Photo put together this wonderful cheat sheet explaining the relationship between camera shake and focal length.
iPhone SLR Mount - Forget about the fact that you're going to have to carry around a big ol' lens. The iPhone SLR Mount is here to give your iPhone access to Nikon or Canon lenses for supposedly awesome quality photos