Reservist Maj. Darryl Watts is accused of playing a role in the death of a fellow soldier at a training range just north of Kandahar city in February 2010.
He pleaded not guilty to six charges, including manslaughter.
Four other soldiers were also wounded when Claymore explosives (C19s) packed with 700 steel balls hit a Canadian Forces platoon.
- Watch the footage at the top of the story of Exhibit 27 from the court martial case. It shows the training exercise Cpl. Joshua Baker was taking part in when he was killed. (Courtesy Canadian Forces)
Watts, who was a captain at the time, was the officer in charge on the day of the accident.
There were four videos made available to the court Friday that were shot by the court martial's first witness of the day, Sgt. Sam Newhook.
He explained that the range was divided into four sections used for training on various weapons, each with a different officer in command and range safety officer.
Newhook clarified for the court that Maj. Watts did not hold either of those titles on any of those ranges that day.
One video shows a platoon milling around as two C19s detonated. Cpl. Baker was killed on the second blast.
Newhook explained proper procedure would have personnel dug in or behind cover, but the video shows that was not the case. In the last moments of the video a person can be heard calling for a medic.
2 others charged
Watts' court martial will be similar to regular court proceedings, except that the judge is a senior military officer and the jury is made up of five other officers who will determine his guilt or innocence.
If convicted, Watts could be sentenced to prison time in the Canadian Force's detention barracks in Edmonton or in a regular correctional facility.
Lesser punishments can include dismissal from the military, a reduction in rank or a fine. Two other Canadian Forces personnel were charged following the accident.
Warrant Officer Paul Ravensdale, who was the safety officer at the firing range, faces identical charges to Watts.
Last September, Maj. Christopher Lunney pleaded guilty to negligent performance of duty while four other charges were dropped.
He was demoted to captain and received a severe reprimand.