(written from a Production point of view)
Singer's directorial career spans more than thirty years, from 1960 to 1998. His credits include The Fugitive, The Monkees, Mission: Impossible, Wonder Woman, Remington Steele, In the Heat of the Night, Walker, Texas Ranger, Jake and the Fatman, many soap operas, and MacGyver.
According to both Garrett Wang and Robert Picardo, Singer had an unusual method of directing while filming episodes of Star Trek: Voyager. After a take was over, instead of verbally talking to the cast about what they did wrong in a scene, he would make strange facial expressions at them. It was his way of telling them they were being too expressive during a scene.