The brand of the digital camera can make a difference-just look at my older photos taken before early July 2008 with a Hewlett Packard R607-none of the photo metadata shutter speeds were ever logical or correct, and there were other metadata anomalies.
Conversely, Ken's system works just fine with my Canon A720IS photos; no metadata errors, issues or problems noted. Like you, I have also noted some camera brands yield no photo metadata here.