The reasons that make me believe that he isn’t smiling are:
The fact that JBC and Jackie both have expressions of concern.
By virtue of what others are doing means JFK did the same? Even if Jackie's change in expression between Willis 04 and Croft was one of concern, she could be worried some people in the street are about to be mowed down by Martin's motorcycle.
In any case, there is no clear indication that Jackie's expression does change between Willis 04 and Croft.
Jim Towner Slide | | Willis 04 Slide (Z157) | | Robert Croft Slide (Z202) |
We can compare the Jim Towner and Croft slides because they of comparable quality and focus:
There is a slight change but Jackie is still smiling. And I would say no look of concern. She might have been smiling a little more in the Towner slide because Tina Towner was filming her.
Governor Connally doesn't appear to have smiled since Main and Houston. He's probably feeling the effects of 30-minutes in that jump seat.
JFK, JBC, Jackie, Nellie, and two SS agents are looking around as if they just heard the first shot and are wondering what it was.
There was also a crowd of people to their left who were hoping to make contact as the limousine straightened up. They were possibly waving and shouting as it was their turn to be seen by the Kennedys. In the early Z-140s, Nellie makes a small turn to look forward. Not a big deal.
Which SS agents are turning? Myers and Vaughan address the turns of Ready, Bennett and Hickey
here. Kellerman straightens his head up in the late-Z140s, where it remains, slightly looking towards his right, as they approach the sign.
JFK nods his head in apparent acknowledgment of the people on his right, who are likely making a lot of noise trying to get his attention. Then he apparently breaks into a smile as if he is returning his attention to the admiring crowd.
Here are the three clearest frames before the "break out in a smile" frame of Z167 (the hand-lifting begins Z170). No rationale have been given for the claim that Kennedy has a "look of concern" or even that he's not smiling in those frames.
People have been interpreting the Zapruder for over 55-years. If you believe the shadows are making it only appear that he is breaking into a smile, that is okay with me. I just don’t agree.
Mockery. I see. Kennedy is already smiling before he turns his head rightward to the crowd (and maybe smiling while he was looking leftward). The change in shadow on his face as his head got to its position in Z167 made it seem he broke out in a smile that moment.