An optimal multihump filter for photometric redshifts

We propose a novel type of filter for multicolor imaging to improve on the photometric redshift estimation of galaxies. An extra filter-specific to a certain photometric system-may be utilized with high efficiency. We present a case study of the Hubble Space Telescope's Advanced Camera for Surveys a nd show that one extra exposure could cut down the mean square error on pho tometric redshifts by 34% over the z <1.3 redshift range.