Simple proof that the Zapruder film is 100% Authentic!
Over at the Ed Forum, there is a few threads pushing that the Zapruder film is faked and the latest "proof" comes from Sandy Larsen, Sandy believes that because Zapruder frame 310 and frame 311 have background elements with varying focus and/or motion blur as compared to the Limo, this must mean that the film was altered. As far as I can tell Sandy believes the reason for this "anomaly" is to hide the Limo stop but a technical explanation of how this was done and the reason for this selective blurring is never explained?
As the Limo travels down Elm, Zapruder pans his camera and attempts to keep the Limo within the frame but because Zapruder just had a hand held camera, his panning was naturally erratic, so the limo within the frame drifts/jerks left and right and up and down but by examining each example of conflicting blur, we see that every motion of Zapruder's handheld camera is directly linked to the Limo and each stationary or moving background object and this provable per object independent motion blur is definitive proof of the films authenticity.
These are the two frames that Sandy presents as evidence of alteration(EDIT I replaced the Zapruder frames because Sandy used the Costello frames which with oversaturated colour and a silly distortion are not worth any serious scientific examination), and we can see the people in the background have become a blur, whereas the limo stays in focus?
As Zapruder horizontally pans to the right he is more or less matching the speed of the limo and the Limo stays in focus but in the following frames Zapruder randomly pans right and up, so as the people in the background are independently moving diagonally down towards Elm as opposed to Zapruder's camera simultaneously panning upwards creates motion blur on the background runners, these alternate opposite movements create scientifically accurate motion blur and on a frame by frame basis no less and this level of infinite precision exists within every side by side frame where this "anomaly" is present. Additionally if you look closely at these two frames it's clear that the frame with the background runners showing motion blur has the limo crisp and when the background is sharp, the Limo and it's occupants show a small amount of motion blur. This highly dynamic co-ordinated relationship between Zapruder's random camera moves and the motion blur of each and every object that he filmed is something that cannot be recreated in a lab, the harmonious motion blur seen on each and every object in the Zapruder film is it's greatest proof. Thanks Sandy!
Let's see how these independent objects(camera, background people and Limo) behave in the preceding frame Z309 as compared to Z310 and here we see the angular velocity of Zapruder's camera is slightly exceeding the Limo's speed as it moves down Elm street but this time with next to zero vertical deviation as expected the people in the background who are equally moving down and to the right, stay in approximately similar focus.
JohnM