Richard Vetter's TODD-AO 35 lenses won an Academy Award for reducing anamorphic distortion in close-ups. Vetter also designed the D-150 process used in Patton (1970).
Director Roman Polanski's wife, actress Sharon Tate, was murdered by Charles Manson three years before the making of the film. It is believed that due to this traumatic event, Polanski developed the story to be a more violent representation of Shakespeare's play. For instance, the scene in which Macbeth murders King Duncan was not in the original play and was instead implied.
During the set up of the gruesome death scene of Lady MacDuff's children, director Roman Polanski was instructing a four-year-old blonde girl on how to play dead, while smearing tons of fake blood all over her body. Polanski playfully asked the girl what her name was, to which she replied, "Sharon".
The scene in which Macbeth's thugs massacre Macduff's household was based on Roman Polanski's memory of SS officers ransacking his house as a child.
When crew members suggested to Roman Polanski that perhaps the film was too unrealistically gory for its own good, Polanski reportedly replied, "I know violence. You should've seen my house last summer."
Roman Polanski wanted to include a violent bear-baiting sequence but it posed all kinds of problems. The first bear they tried to use was too timid and kept running away from the dogs, while the second was uncontrollably vicious and pawed a crew member. He eventually opted for an intrepid stuntman in a bear suit, but understandably the man would only agree to a single dog being set loose on him, fearing his armored padding wouldn't be up to the job. Polanski secretly instructed the handlers to loose three dogs, sending the stuntman cowering in fear, screaming at the director to call them off.
Filming began with four grueling weeks in Snowdonia National Park. A cameraman was nearly killed on the first day when a fierce wind blew him into a crevice.
Act Three, Scene Five of "Macbeth" is an interpolation, an addition to the Shakespeare play from another script. Generally it is not used in theatrical and movie adaptations for this reason.
The lyrics to the song that Fleance sings at Macbeth's banquet for Duncan at Inverness are taken from the poem "Merciles Beautè" by Geoffrey Chaucer.
The very first "Playboy Production" for the cinema.
Roman Polanski owned a painting by British artist Michael Worrall, which gave him the inspiration to make the movie. The second scene was based on this painting.
Director Roman Polanski originally sought Tuesday Weld for the role of Lady Macbeth. She refused to do a nude sleepwalking scene so he cast Francesca Annis in the part.
In her memoirs Marianne Faithfull recalls screen testing for the role of Lady Macbeth at the request of Roman Polanski. However when her heroin use became obvious to Polanski during the test she lost the role.