All long takes pale in comparison to this one. It's from the BBC's acclaimed mini-series
I, Claudius. A bit of backstory so you'll understand the scene. Augustus (Brian Blessed), Emperor of Rome is married to Livia (played to Machiavellian precision by Siān Phillips) who has been trying to get Augustus to adopt her eldest son Tiberius, offspring from her previous marriage, so that he can be Emperor upon Augustus' death. Augustus has delayed in making that decision, as there are other blood relations ahead of Tiberius in the line of succession. Slowly and methodically over the previous years, Livia has been finding ways to do away with these potential rivals for the throne of Rome. Finally, after realizing that no legitimate blood heir is left, Augustus acquiesces to Livia's wish and he adopts Tiberius. Knowing that Livia, who has a predilection towards poisoning people, now will more than likely poison him, he takes to picking his own food in his garden. He's especially fond of Figs and Livia finds a tasteless and scentless, slow acting poison and she brushes it on the fruit of one of Augustus' Fig Trees in the garden. Unknowing of this, Augustus picks a huge bunch and eats them. In this scene, he's slowly dying, all the while having to listen to Livia harp about why he should have just listened to her in regards to Tiberius. Augustus knows she has poisoned him, but there's nothing he can do now, he's doomed. He's resigned to his fate and Blessed plays this death scene like no other, before or since. The camera stays on him throughout its duration and you see death slowly taking hold. I've seen countless death scenes, but none compares to this. He dies at the 1:45 time stamp in this clip and holds that soulless stare for an additional 1:50. He never blinks, twitches or breathes. It's the most remarkable scene I've ever watched in anything. What truly makes it remarkable is that he had done a previous take and was spot on in that one, but something wasn't set up properly and they had to re-shoot it. Without flinching or getting angry, Blessed repeated the same perfect performance. If you've never seen
I, Claudius, you really need to rectify that, it's one of the BBC's best productions ever!
https://youtu.be/mrl4PecqM00And a note about Livia (Siān Phillips). Phillips gives the most amazing performance as the vile, venomous Medusa like wife who plots and schemes to keep power in Rome. Her character is in the first six episodes and for the first five you hate the mere sight of her, because you know she deserves to die a horrible, painful death. When her time comes in the sixth episode, you actually feel pity for her while she's on her death bed. The death soliloquy, as recited by Phillips is delivered in such a manner that you actually hope here final wish is granted, to be declared a goddess by her nephew Caligula. Only a true thespian can make you feel pity for such a loathsome, vindictive witch. And Phillips delivers that once in a lifetime performance!