Photometric redshifts (z_B) vs. spectroscopic redshifts (z_spec) in the deep calibration fields. Left: original KiDS-450 photo-z based on ugri-band photometry. Middle: improved ugri-band photo-z based on the Bayesian prior by Raichoor et al. (2014). Right: KV450 photo-z based on ugriZYJHK_s photometry as well as the improved prior. The grey region of the figures indicate sources beyond the z_B limit imposed in the KiDS-450 analysis. Annotated in each panel is: the normalised median-absolute-deviation (σ_m) of the quantity (z_B − z_spec)/(1 + z_spec)≡Δz/(1 + z), the fraction of sources with |Δz/(1 + z)| >  3σ_m (η₃), and the fraction of sources with |Δz/(1 + z)| >  0.15 (ζ_0.15). Each of these quantities is calculated individually for the sources above and below z_B = 0.9. The value of σ_m is also displayed graphically in each panel using the black dotted lines. We note the significant improvement in all quantities that is seen when moving from the 4- to 9-band photometry, and in particular that we are now able to constrain z_B >  0.9 sources to almost the same accuracy as those z_B <  0.9 in the original KiDS-450 dataset.