The film invested 17 million US dollars, which is a low-cost production. For director Joel Schumache , who is good at dealing with low-budget productions, this will not be any hindrance. What's more , Jerry Bruckheimer, the producer who once undertook "Pearl Harbor" and "Black Hawk Down" , guided behind the scenes, which has made a good guarantee for the quality of the film.
During filming, production designer Nathan Crowley and photographer Brendon Garvin both tried their best to create a convincing sense of realism. According to Gavin, some people think realism means shooting with a handheld camera, like a documentary. He didn't think that approach was suitable for the film, and throughout, they were shooting with two cameras, which helped with the cast, the story, and the continuity. They wanted cloudy skies and struggled to find reflective surfaces, Crowley said. They have been working hard to make Dublin look like a big city and present the city in a different light.
