Impact of depth on the redshift confidence assignment. The Lyα line (data in blue color, fit in red color) and the corresponding narrowband image of the Lyα emitter MID-690 are shown for the UDF-10 (left column) and the MXDF (right column) data sets. The green curves display the noise standard deviation. The narrow bands have been smoothed with a Gaussian of 0.5″ FWHM. Image sizes are 5″ × 5″. Observed wavelength and flux units are respectively Å and 10⁻²⁰ erg s⁻¹ cm⁻² Å⁻¹.