I have recently combined HST STIS spectrophotometry with existing photometric data to analyze the calibration of three standard optical photometry systems: TYCHO-2 BTVT, Strömgren uvby, and Johnson UBV. In this contribution I summarize those results, present new ones for 2MASS JHK_s, and combine them with recent literature results to generate a uniform set of zero points for six photometric systems, the above mentioned plus Cousins RI and SDSS ugriz. With the exception of the latter system, the zero points use the new Vega spectrum presented at this meeting by Ralph Bohlin. I also discuss the implementation of these results in CHORIZOS, a Bayesian photometric code that compares multi-filter observational data with spectral energy distributions to solve the inverse problem of finding the models which are compatible with the observations.