This study evaluated the efficiency of a new E/F-speed film, Insight, at the determination of approximal carious lesion depths compared with Ultraspeed. Radiographs of 80 extracted human molars and premolars were taken with both films under standardized conditions. The presence or absence of caries and depth of lesions was determined by three observers using a predetermined scale. The actual status of each surface was determined histologically. Observer responses were assessed with the Gamma measure of association test. Differences between the observers' agreement levels were not significant.