The Johnson criteria have been shown to be fundamentally flawed due to their insensitivity to effects below the limiting frequency. This flaw makes predictions for many modern imaging systems inaccurate. A new target acquisition metric, the targeting task performance (TTP) metric, has been developed that provides better accuracy than the Johnson criteria. Further, unlike the Johnson criteria, the TTP metric can be applied directly to sampled imagers and to imagers that exhibit colored (spectrally weighted) noise due to frequency boost. Experimental data using both target recognition and target identification tasks show the problems with the Johnson criteria and illustrate the robust performance of the TTP metric. The simplicity of implementing a range performance model with the Johnson criteria is retained by the TTP metric while extending applicability of the model to sampled imagers and digital image enhancement.