  I have recently combined HST/STIS spectrophotometry with existing photometric
data to analyze the calibration of three standard optical photometry systems:
Tycho-2 B_TV_T, Stromgren 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.
