This question really boils down to a more general one: What
degree of photometric precision can be achieved by a smartphone
camera? To put this question in context, let me give a brief
explanation of what is fundamentally different about a
scientific image sensor versus a consumer grade sensor. As you
would expect, a scientific CCD will usually have much higher
quality than a consumer grade CCD. In this context, "quality" is
quantified by dozens of characteristics of the CCD, such as the
uniformity of the sensitivity of each pixel, dark current,
defective pixel count, photoelectron well depth, electron lag,
spectral response, bleed and saturation, etc. The superior
performance of a scientific CCD is, of course, helpful in making
a good measurement; but the really critical distinction of a
scientific CCD is that each and every property of the CCD will
be measured and tested before the CCD is ever put into use. In
fact, when purchasing a scientific CCD one receives many pages
of documentation detailing each cha