Imaging systems have advanced significantly in the last decades in terms of low noise and better resolution. While imaging hardware resolution can be limited by collection aperture size or by the camera modulation transfer function (MTF), it is the atmosphere that usually limits image quality for long range imaging. The main atmospheric distortions are caused by optical turbulence, absorption, and scattering by particulates in the atmosphere. The effects of the turbulent medium over long/short exposures are image blur and wavefront tilts that cause spatio-temporal image shifts. This blur limits the frequency of line pairs that can be resolved in the target's image and thus affects the ability to acquire targets. The observer appears to be able to ignore large-scale distortions while small-scale distortions blur the image and degrade resolution. Resolution degradations due to turbulence are included in current performance models by the use of an atmospheric MTF. Turbulence distortion effects are characterized by both short and long exposure MTFs. In addition to turbulence, scattering and absorption produced by molecules and aerosols in the atmosphere cause both attenuation and additional image blur according to the atmospheric aerosol MTF. The absorption can have significant effect on target acquisition in infrared (IR) imaging. In the present work, a brief overview and discussion of atmospheric effects on target acquisition in the IR is given.