The shutter lenses in Spider-Man's home-made suit from Captain America: Civil War and Homecoming couldn't have really been made by a teenager - but they served a bigger purpose in the film that made their inclusion essential.

Along with making Peter Parker a full-on high-school student, one the biggest changes to the MCU version of the web-slinger was his suit. Spider-Man's main costume was a high-tech product of Tony Stark, with his home-made one so rudimentary it earned him the nickname "underoos". One thing shared by both versions, however, was the shutter eyes that adjusted the size of the iris based on context. How Peter developed this tech isn't made clear in the movie and it seems wasn't a major concern when the effect was being designed either.

Related: Why Spider-Man’s Homemade Suit is Important to Homecoming

Screen Rant recently talked with Theo Bialek, visual effects supervisor on Homecoming, about his work on the home-made suit and specifically how his team approached the shutters. Bialek revealed Peter actually making these wasn't a concern, rather their practical purpose in the story - allowing Spidey to emote with his mask on:

Screen Rant: How did you justify that being made by a teenager?

Theo Bialek: "Didn't really [laughs]. The iris shield - I think that was one of the things that I feel that Marvel brought to us. You wanna keep your relatable and be able to emote and I think that that was the mechanism for it, regardless of the suit. Look, when he has the hood and you can't see his face, you still want to be able to have him emote and get those laughs or the subtlty and the expression that you don't have when he has a mask on - if you have iris-closing eye shields you can simulate that. So I think that was the prime focus of that."

Spider-Man Homecoming Tom Holland and Prelude Comic

The shutter eyes are highly evocative of the early Spider-Man artwork of Steve Ditko, who would alter the size of Spidey's eyes panel-to-panel to help convey emotion. This was a barrier in previous big screen outings for the character and somewhat played into Tobey Maguire and Andrew Garfield's Peter constantly removing their mask for major sequences. Introducing the shutters, then, was not only a form of comic book homage but allowed for a more authentic, involving version of the web-head.

Of course, while Bialek says there wasn't excess thought put into making sure the shutters had a real-life mechanism, and one that could be built by a teenager from Queens, this is Peter Parker we're talking about. In the comics, he was able to build a high-tech suit with ease and in the MCU still has developed his own webbing, so it's within the realm of possibility he'd be able to mock it up from all those computer parts he's hoarding.

In our talk, Bialek also talked about another fantastical element of the film that was realized - the Vulture's suit. Based on real jetpack technology, to get the general physics of movement the team looked at a variety of real-world examples: "There's a Dubai jetpack guy who flies around, Jetman I think he's called. We would look at that as well as squirrel team people jumping off cliffs and flying around."

Next: Marvel Has VFX “Crash Course” For Indie Directors New To CGI

Spider-Man: Homecoming is available now on Digital and releases on 4K Ultra HD /Blu-ray, Blu-ray 3D, Blu-ray and DVD.

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