Converts retinaldehyde to retinoic acid. Recognizes as substrates free retinal and cellular retinol-binding protein-bound retinal. Can metabolize octanal and decanal, but has only very low activity with benzaldehyde, acetaldehyde and propanal. Displays complete lack of activity with citral. H2O + NAD(+) + retinal = 2 H(+) + NADH + retinoate Cofactor metabolism; retinol metabolism. Homotetramer. Belongs to the aldehyde dehydrogenase family.