We evaluated new colour transformations for the Sloan photometry by 224 standards and used them to revise both the equations for photometric parallax estimation and metallicity calibration cited by Karaali et al. (2003). This process improves the metallicity and absolute magnitude estimations by [Fe/H] ≤ 0.3 dex and Mg′H ≥ 0.1 mag respectively. There is a high correlation for metallicities and absolute magnitudes derived for two systems, UBV and Sloan, by means of the revised calibrations.