Comparison of the reached depth in the observed J-band images with the expected CAHA J-band magnitude of early type ellipticals, depending on their redshift. We plot the expected CAHA J-band magnitude of early type ellipticals against the redshift corresponding to M^* + 0.5 (solid red line) and the nominal magnitude of such a galaxy at redshift z ∼ 1.1 (dashed red line). The shaded areas are the acquired 10σ (vertical green), and 5σ (diagonal blue) depth ranges of all targets.