Camera Shake under Stress: Moving Targets Viewed Briefly in Poor Light

Groups of 16 and 8 people photographed octobar targets which moved horizontally at rates of between 0 and 1 in. per sec. The illumination was 1·6 ft candles. With moving targets there was a statistically reliable increase in blur in both the horizontal and the vertical dimension. The increase in blur in the horizontal dimension was Smaller than was to be expected from the movement of the target. People must have tracked the target while taking the photographs. The increase in blur in the vertical dimension represents an increase in camera shake. Placing a 2·45 neutral density filter over the viewfinder made no difference to the blur. People were consistent in the amount of shake which they produced on 2 occasions separated by 1 month. There were no consistent differences between sexes or ages.