There has been some discussion of what can be seen in the Zapruder Film and I would like to add my 2 cents worth.

The copy of the Z film available from The Center for Action is incomplete and many generations old, making it impossible to determine anythiong about what is occurring. I have written to the Center and complained about this. 

It is my belief, based on a very clear copy of the film that I have, that the theory that the driver fired the fatal shot is untrue. Clearly the use of a chrome plated .45, as some suggest was used, would be idiotic. It would be very visible and eject shells, perhaps into the street. More importantly, the film, as it exists today does not support that theory.

A clear copy of the film may be obtained for research purposes from DHL Films, on Olympic in LA, possibly also called B.E. Video. If this does not pan out the correct addres is in the back of the second edition of DAvid Lifton's BEST EVIDENCE, it's the same address as his Best Evidence video. The cost is about $13.00 and it is on VHS. It is the best copy of Z vailable to the public, and it is complete.

There are plenty of mysteries in the film without inventing and more.
1. Why are there obvious mid frame splices when the road sign is in frame.
2. Why does the PResident have a large red waterballlon on his forehead after the fatal shot hits.
3. Why are frames missing just after the fatal shot hits. (I believe it was to obscure something about Connally.)

As for the number of films shot then:
Zapruder,
Orville Nix,
Muchmoore,
(sorry about the spelling)
Beverly Oliver.
All shot motion pictures. Zapruder's went through goverment hands prior to processing. Oliver's was confiscated, I believe by an FBI agent named Regis Kennedy,and never seen publicly, and I believe it is unavailable permanently.
 Nix and Muchmore's are around. There are some 500 or so stll shots in the plaza of some relevance according to some sources. There was also a UPI film shot from a follow up car and a film that shows the Presidential limo after it has gone under the overpass. there may be one additional film i cannot recall. Only Beverly Oliver's is missing. (and she had a fantastic view standing very near Moorman the women who took the famous polaroid.

There is much to be learned, has anyone noticed the dissappearing boxcar?
Check the stills carefully. How about the structure in the trees?

 The secret service was well behind the Presidential car for a very simple reason. They did not want to get shot.

 There are pictures of the agents pulling weapons, which look roughly like AR-15s (M-15's?)

As for Mr. Zapruder, He, and his family today, maintain the copyright on the film and set a high price on it. That is why it has been so hard for the public to see. Personal Avarice. (And I think there's a lesson in that for UFO oriented folks when it comes to videotapes...)