Oswald in the doorway: the blog of the Oswald Innocence Campaign, by Ralph Cinque

The start of Weigman and the snapping of Altgens were so close that they were practically simultaneous. People argue about which came first. 

They were very close, within a second or two, and you can't assume that Doorman moved. Why? He was watching the motorcade. In both, JFK was already down Elm St. being shot at it. You have no basis to assume there was any difference between them. 

Here is Doorman's real position in Altgens:

And as you can see, it's a very good match to what we see in Wiegman. His left shoulder was sheared off by the placement of Black Tie Man into the photograph.