In this work I discuss the necessary steps for deriving photometric redshifts for luminous red galaxies (LRGs) and galaxy clusters through simple empirical methods. The data used are from the Sloan Digital Sky Survey (SDSS). I show that with three bands only (gri) it is possible to achieve results as accurate as the ones obtained by other techniques, generally based on more filters. In particular, the use of the (g-i) colour helps improving the final redshifts (especially for clusters), as this colour monotonically increases up to z~0.8. For the LRGs I generate a catalogue of ~1.5 million objects at z<0.70. The accuracy of this catalogue is sigma=0.027 for z<=0.55 and sigma=0.049 for 0.55