Production began on June 28, 2010.[82] On the same day, Marvel confirmed that Tommy Lee Jones had been cast to play US Army Colonel Chester Phillips.[16] The next day Marvel confirmed that Dominic Cooper would portray the younger version of Howard Stark, the character played by John Slattery in Iron Man 2.[83] It was announced that the film would shoot in London in late July and was expected to include scenes featuring key London landmarks.[84] War scenes were filmed in September at the former Royal Navy Propellant Factory in the Welsh village of Caerwent.[85][86] Filming was scheduled to take place that month in the Northern Quarter of Manchester, where parts of the 2004 film Alfie and the 2009 Sherlock Holmes had been shot,[87] followed by the Stanley Dock area of Liverpool, both doubling for the period's Lower East Side of Manhattan.[88] Further scenes were scheduled to be shot in Liverpool's Albert Dock.[89] Johnston included a scene of a technology fair that includes in passing a display case containing the 1940s android superhero known as the original Human Torch, another character, like Captain America, in comics published by Marvel Comics' predecessor, Timely Comics.[90]
In July 2010, Marvel Studios head Kevin Feige said that both this film and Thor would be released in 3-D.[91] Johnston did a one-day test shooting with a 3-D rig, rather than shooting in 2-D and converting, and found it "a nightmare" due to bulky gear, calibration issues and restricted filmmaking options. Nevertheless, he said he believes 3-D is "a new challenge and it's exciting". Feige insisted that the conversion would not compromise the film's image quality, as the decision to release the film in 3-D was made early in development, and that "an unprecedented amount of time" would be devoted to the conversion process, to render all the film's visual effects in true 3-D.