During his Clay-Shaw testimony Zapruder also testified that he could see the JFK Motorcade coming down Houston and then turning onto Elm.
He was just not experienced with the camera. It was amazing that he filmed anything at all without completely choking the technique of viewing while pressing the shutter button. So, he could 'see the car as it turned' but did he
film the car as it turned? Did he say that? Or was it simply a case of low self esteem because he forgot to start filming the movie at the onset?