Mounting an SLR lens to an iPhone sensor would produce worse results than using the default lens. The imaging sensors used in cell phones are much smaller than

Mounting an SLR lens to an iPhone sensor would produce worse results than using the default lens. The imaging sensors used in cell phones are much smaller than SLRs, so you'd need to get a much wider angle lens. Then, you'd only be using the center of the lens, which the sensor would outresolve anyway.