Thanks, that’s interesting. However it appears to me that, in his handbook, page 17, Mark Tyler explains that this is just a rough estimate. Here’s a quote:
4.3.3 Zapruder & Wiegman
Circa Z447 (see appendix E.11) is a very interesting point in the
animation as it roughly synchronizes the Wiegman film with the
Zapruder film.
And this is from appendix E.11:
I believe that Dale Myers’ methodology is considerably more involved and exact. I certainly don’t remember all the details but he did document his methodology very well. Take a look for yourself if it interests you.
I would suggest that Myers’ synchronization is “rough”. He doesn’t seem to know what the term “margin of error” or “significant figures” mean. He throws around numbers with three significant figures like .671 degrees per frame without acknowledging any uncertainty.
By contrast, Tyler has a margin of error of about 7 zframes for his placement of the start of Wiegman’s film in front of the TSBD (from z280 to z287).
Myers says that the beginning of Wiegman’s sequence in front of the TSBD was 3.66 seconds before the headshot which would put it at z246. The problem is that the Altgens photo taken at z255 shows only back to the VP security car. The Cabell car is not yet in the picture. Yet Wiegman’s sequence begins with the Cabell car having almost completed the turn and the National Press car well into the turn.
So I would suggest that Myers methods are highly questionable and his conclusions not reliable. Failure to state the margin of error, overstating significant figures of accuracy and his generally condescending manner are big red flags for me.