Magnitudes as a function of photometric redshift for the GMASS sample, in the ACS F606W band (top), ISAAC K_s band (middle), and IRAC 4.5 μm (bottom). A straight line is fit to the median of the brightest 5% in each Δz = 0.25 bin, up to z = 1.5, that has a slope of 3.4, 2.0, and 0.9, respectively. This shows the relative strength of the K-correction for these bands, which is strong in V-band, and much weaker in the infrared IRAC band.