For many terrestrial IR imaging applications, speed and sensitivity requirements can be met by several sensor technologies, including PtSi staring arrays, second generation scanned MCT arrays, InSb, and MCT staring arrays. However, for high quantum efficiency staring arrays, MCT and InSb in particular, much of the available signal remains unused because of well-fill restrictions. In narrow spectral band imaging applications the available photon flux is dramatically lower and high quantum efficiency becomes critical. One such application is detection and imaging of gases. High quantum efficiency arrays allow the use of narrow band filters centered on the absorption band of the gas, thus enhancing the ability of the imager to discriminate between background and gas emission. Results of imaging studies performed on a camera with a narrow band filter for gas detection are presented and analyzed.