the present invention relates to a portable , hand - held distance - measurement apparatus comprising a laser range finder which is aimed by an active viewfinder . the active viewfinder improves the accuracy of the range finder by giving the user more visual feedback and thus allowing the user better control over the ranging operation . under user command , the viewfinder enters a targeting mode wherein the user is presented with a illuminated targeting indicator inside the viewfinder . the indicator is superimposed upon the field - of - view seen through the viewfinder . in the targeting mode , the user aims the range finder by placing the targeting indicator on the object to be ranged . once the device is aimed , the user commands the distance - measurement device to execute a distance measurement cycle . in one embodiment , targeting indicator flashes in various ways to indicate the quality of the data being obtained during the distance measurement cycle . when enough data has been obtained to compute the distance , then the targeting indicator turns off , letting the user know that the display has been updated .