Filmed by an active-duty US Army chaplain stationed in Afghanistan and focusing on soldiers of the 101st Airborne Division’s “No Slack” battalion, the documentary 'No Greater Love' is a remarkable film about war and its effect on soldiers.

As a chaplain, director Justin D Roberts did not carry a weapon, but instead used a camera to gain unparalleled access to intense combat stories and to open a discussion of resultant psychological trauma.

Interspersing war footage with interviews with soldiers and their families, Roberts takes his time to put combat operations in context, with officers describing the tactical nightmare of fighting in a mountain range with limited visibility and few escape routes.

Most of the film focuses on two missions that sustained heavy casualties. As soldiers recall each excruciating detail, they get emotional on camera.

Most war documentaries are made by civilians, which can make the storytelling stilted, as soldiers pause to explain military jargon.

Because the interview subjects in 'No Greater Love' speak without interruption, their recollections are all the more natural and vivid.

They hold nothing back, describing mutilated bodies and frustration with the rules of engagement. Some openly weep, heartbreakingly.

Despite his extraordinary access, Roberts is not a natural documentarian. He uses a sermon as an awkward framing device. Interviews often cut to him listening intently, which interrupts the flow.

Still, 'No Greater Love' gives us insight into why a soldier might choose to deploy again after recuperating from a traumatic brain injury.

It shouldn’t be revolutionary to let ordinary soldiers share their experiences in their own words, but somehow it is.

'No Greater Love' gets at the camaraderie — and the contradictions — of military service in a way few films have.