So he created a new medium.
His startup, Condition One, has developed a video player for the iPad and iPhone that gives users some control over how they view a scene.
Viewers don't just passively watch a window as they do with existing players. Rather, they can control video almost as if they are holding the camera. When they pivot or tilt their devices to the right, the video pans to show what they would see if they had turned their heads to the right from within the scene. The same goes for every direction (you can sample the experience with this iPad app).
Early on, Dennis spoke of the product in relation to his work documenting war. As a photojournalist in Iraq and Afghanistan, he contributed images to publications such as The New York Times and Time. He later switched to a video camera, which he used to direct an Oscar-nominated documentary film that follows a solider who was injured during the War in Afghanistan.
"Through our work we hope to shake people from their indifference to war, and to bridge the disconnect between the realities on the ground and the public consciousness at home," Dennis said about Condition One.
His current client list, as he says was originally intended, is a bit broader. It includes Mercedes, Discovery Communications, XL Recordings, The Guardian and Popular Science, which recently used the player to give a virtual tour of a particle physics experiment.
But the illusion of immersion adds a layer of understanding to particle physics just as effectively as it could war.
"[Video] is often a very guided experience, where this is an immersion experience," Dennis says. "It gives you more of a sense that you're there. Which is something I couldn't convey with film."