In Orson Welles' Othello there is little tinkering with the source material.
Explanation:
Whenever a book or a film is done over film there have to be certain changes made just to accommodate the film to the form of the play and to accommodate the changes in the medium that are there.
The changes here in the film are the elaborate sequences by which Othello has not been a merchant at sea but a powerful businessman at the city and Iago is his consulate in a way in the town.
The characters are not seamen but regular merchants on the land.
