In the past ten years there have been very promising advances in the state-of-the-art in aerial reconnaisance both in the airborne systems and in ground data handling. However, the physical world restraints of resolution still make the conventional film camera the prime sensor in aerial reconnaissance. Ground resolution and working scale required for specific items of information are fixed. The electro-optical system, IR system, radar system, or the photographic system must meet the image data requirements in order to be useful. Detector physical dimensions and phosphor minimum grain size limit the system resolution element size. Information theory describes the limits on resolution elements required for various levels of detection, recognition, and identification. The achieved system performance includes all factors which affect resolution when the system is flown. Information theory accounts for the difference between in-flight resolution and laboratory resolution. Computer availability has facilitated polar plot depictions of airborne system performance that permits lens aberration effects and window thermal gradients to be studied as well as system resolution performance in terms of system parameters. The very large information content and the immediate interpretability inherent in film sensors make conventional cameras the prime clear daylight sensor for now and for the projected next ten year period.