Jerry,
let's examine that possibility.
Croft #18 is the equivalent of Z161 - no shot had been fired.
Betzner #3 is the equivalent of Z186 - he took his photo just before the FIRST shot was fired.
"I took another picture as the President's car was going down the hill on Elm Street. I started to wind my film again and I heard a loud noise. I thought that this noise was either a firecracker or a car had backfired. I looked up and it seemed like there was another loud noise in the matter of a few seconds. I looked down the street and I could see the President's car and another one and they looked like the cars were stopped."
Betzner said he was looking down to wind his camera when he heard the first of
two shots he later recalled, the latter one being the head shot based on what Betzner said about it. So the winding-the-camera shot he heard would be the shot heard before the head shot (ca. Z223). In a three-shot scenario, Betzner has lost track of one of those shots.
As Betzner goes out of the Zapruder film in Z207, he is still lowering his camera and is not looking down. So Betzner winding his camera as he hears a shot does not relate to your belief that a first shot occurred Z187-Z201.
Assuming he winds his camera shortly thereafter (Z207 when he goes out of view), it would be an argument that the shot he heard while winding the camera was the proposed SBT shot at Z223.
Willis #5 is the equivalent of Z202
Willis snapped that photo as a result of hearing the FIRST shot.
Hence the FIRST bullet was fired between Z187 - Z201
For the SBT to even be remotely possible, the FIRST shot absolutely had to have missed everyone in the Limousine despite the Presidential Limousine being the closest to the TSBD building at that point in time.
Max Holland went one step further back - he believed the FIRST shot took place even before Zapruder started filming the Limousine coming down Elm Street. That's BEFORE Z133. He further believed that the bullet struck the light pole and a part of it went onto strike Tague.
There is a multitude of problems with that scenario because that's even before Croft #18 at Z161 and there is no indication that anyone is even remotely reacting to anything fired literally above them at pre Z133.
However between Z187 - Z201 is interesting because:
Mr. WILLIS. No, sir; I took that picture just seconds before the first shot was fired, to get back close up. Then I started down the street, and the regular weekly edition of Life magazine came out and shows me in about three different pictures going down the street. Then my next shot was taken at the very--in fact, the shot caused me to squeeze the camera shutter, and I got a picture of the President as he was hit with the first shot. So instantaneous, in fact, that the crowd hadn't had time to react.
Willis: When I took slide No. 4, the President was smiling and waving and looking straight ahead, and Mrs. Kennedy was likewise smiling and facing more to my side of the street. When the first shot was fired, her head seemed to just snap in that direction, and he more or less faced the other side of the street and leaned forward, which caused me to wonder, although I could not see anything positively. It did cause me to wonder.
Mr. LIEBELER. You say that the President looked toward his left; is that correct? Toward the side of Elm Street that you are standing on, or which way?
Mr. WILLIS. In slide No. 4 he was looking pretty much toward--straight ahead, and she was looking more to the left, which would be my side of the street. Then when the first shot was fired, she turned to the right toward him and he more or less slumped forward, and it caused me to wonder if he were hit, although I couldn't say.
Willis, who's very near to Mrs. Kennedy between the taking of his 04 (about Z133) and 05(Z202) photos, describes what occurred during that interval:
 "Mrs. Kennedy was likewise smiling and facing more to my side of the street." | |  "When the first shot was fired, her head seemed to just snap in that direction ... she turned to the right toward him" |
Above: Three frames showing when Mrs. Kennedy began her rightward head turn, the head turn described by Willis as a reaction to hearing the first shot.
Miss WILLIS. Yes; I heard one. Then there was a little bit of time, and then there were two real fast bullets together. When the first one hit, well, the President turned from waving to the people, and he grabbed his throat, and he kind of slumped forward, and then I couldn't tell where the second shot went.
Mr. LIEBELER. Now, you were standing right along the curb on Elm Street, is that right, when the motorcade came by across the street from the School Book Depository Building?
Miss WILLIS. Yes, sir.
Mr. LIEBELER. Did you follow the motorcade down Elm Street at all, or did you stand on the corner up toward Houston Street and watch from there?
Miss. WILLIS. I was right across from the sign that points to where Stemmons Expressway is. I was directly across when the first shot hit him.
Mr. LIEBELER. Directly across from the sign that says, "Stemmons Freeway"?
Miss WILLIS. I was right in line with the sign and the car, and I wasn't very far away from him, but I couldn't tell from where the shot came.
That's the testimony of Linda Willis. She can't see the President when he's between her and the Stemmons sign. She could, however, see the President when he was between her and the Thornton sign.
She might have later thought it was the Stemmons sign because of her father's famous photo, which features that road sign.
