In this paper incorporation of atmospheric aerosol and turbulence effects into visible and infrared search modeling is considered. Here, we show how the target acquisition probabilities and, conversely, the ranges at which targets can be detected are changed by the inclusion of atmospheric effects. It is assumed that images are contrast-limited rather than noise-limited, as is indeed the case with most visible, near infrared (IR) and thermal IR sensors of high quantum efficiency. For short focal lengths with low angular magnification, atmospheric effects on target acquisition are negligible. However, for longer focal lengths with large angular magnification, resolution is limited by the atmosphere and this has a strong adverse effect on target acquisition probabilities, times, and ranges. The considerable improvement possible with image correction for atmospheric blur automatically in real time is significant for contrast-limited imaging, and is discussed here too. Knowledge of atmospheric MTF is essential to good system design. It is also very useful in image restoration for any type of target or object.