Refractive infrared optical designs have traditionally covered modest FOVs in one spectral band. The design of a fast, extreme fisheye lens imaging 360° azimuth by 120° elevation over the full 3-12 micron band is described. The various relevant tradeoffs that were explored are detailed and the advantages and disadvantages of each approach are discussed. In particular, the applicability of reflective and diffractive solutions is described.© (2007) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.