Avengers: Infinity War and the currently untitled Avengers 4 are shooting back-to-back, but the MCU team-ups won't be filming at the same time. Ever since they were officially announced, Avengers 3 and 4 have been treated as a duology; they were first named as Infinity War Parts 1 and 2, and even after the sub-titles were shifted to reflect the movies being less directly connected the pair still felt inexorably linked.
Indeed, the Russo brothers are still directing both movies and they're shooting as part of the same production block. However, despite being so sprawling it's the subject of its own lengthy Wikipedia page, details of this process is a rather closely guarded secret, so it's not been known how exactly the two movies now relate. Based on new comments from Marvel Studios President Kevin Feige, it might be less than some thought.
Speaking with Collider for the release of Guardians of the Galaxy Vol. 2, Feige revealed that the films aren't being shot at the same time, with Avengers 4 only beginning after Infinity War had wrapped:
“We’re doing them one right after another… It became too complicated to cross-board them like that, and we found ourselves - again, something would always pay the price. We wanted to be able to focus and shoot one movie and then focus and shoot another movie.”
This doesn't mean the films are no longer shooting back-to-back, just that there isn't the expected overlap in production; everything shot up until now is just for Infinity War. Feige later told the outlet that Avengers 4 is expected to start filming in August, indicating Infinity War will probably finish around July. On this timescale, each film will take approximately seven months to shoot, fitting of a major tentpole.
There's a lot of reasons why this linear shooting method will have been taken. From a technical standpoint, it means that "lensing" for Infinity War is in the can as soon as possible, allowing the extensive post-production for the cosmic adventure to begin well ahead of its May 2018 release. And, of course, it keeps the costs down - it's like shooting one massive movie rather than two big ones. But, creatively, it reaffirms that these will be separate stories and that the Russos are treating each movie very differently.
What this says of the length of the Infinity Stone arc, which is being cited as the "culmination" of the MCU so far, is unknown. Due to originally being a two-parter, many are expecting Avengers 3/4 to share an overarching narrative (perhaps complete with a cliffhanger), but it's possible that plans have since changed.
Regardless of their connection, both movies are going to be pretty big. Infinity War is already set to have a sprawling cast of characters - it will see the fractured Avengers reforming after the events of Captain America: Civil War and meeting the Guardians of the Galaxy - and based on the heroes already set for its sequel, it sounds like Avengers 4 will be on a similar galactic scale.
- Guardians of the Galaxy Vol. 2 (2017) release date: May 05, 2017
- Spider-Man: Homecoming (2017) release date: Jul 07, 2017
- Thor: Ragnarok (2017) release date: Nov 03, 2017
- Black Panther (2018) release date: Feb 16, 2018
- Avengers: Infinity War / The Avengers 3 (2018) release date: Apr 27, 2018
- Captain Marvel (2019) release date: Mar 08, 2019
- The Avengers 4 / Avengers: Endgame (2019) release date: Apr 26, 2019
- Ant-Man & The Wasp (2018) release date: Jul 06, 2018