Various atmospheric properties can impact sensor performance modeling. Transmission, visibility, and contrast can be used in relatively simple expressions to summarize the impact of the atmosphere on static images. Transmission and contrast can be used together in an expression called the sky-to-ground ratio. Experimental measurements of radiance and imagery are used to assess the applicability of the delta Eddington radiative transfer approximation for estimation of apparent contrast and sky-to-ground ratio. The experiments were performed in southern New Mexico near the autumnal equinox. Delta Eddington calculations are made for two types of aerosol phase functions: Henyey-Greenstein and Deirmendjian haze. Comparisons also include computations from a much simpler radiative transfer model, the Huschke model. These experiments support the use of a relatively simple contrast model that more accurately reflects nature than more empirical models.