def from_sdss_albd_to_megacam_albd(sdss):
    """Return A(lbd) for the 6 Megecam filters: u, g, r, i_old, i_new, z."""
    megacam = {}
    megacam['u'] = sdss['u'] - 0.241 * (sdss['u'] - sdss['g'])
    megacam['g'] = sdss['g'] - 0.153 * (sdss['g'] - sdss['r'])
    megacam['r'] = sdss['r'] - 0.024 * (sdss['g'] - sdss['r'])
    megacam['z'] = sdss['z'] - 0.074 * (sdss['i'] - sdss['z'])
    megacam['i_old'] = sdss['i'] - 0.085 * (sdss['r'] - sdss['i'])
    megacam['i_new'] = sdss['i'] - 0.003 * (sdss['r'] - sdss['i'])
    return megacam