The exercise was planned as a relative descent from an exit altitude of 6000 feet. One parachutist was equipped with a video camera and it was planned that he take a video of the other parachutist during the descent. The exercise was thoroughly briefed and rehearsed on the ground prior to take-off. It was planned that the parachutist being filmed would deploy his parachute at 3000 feet to enable the opening sequence to be recorded on video. The other parachutist would then deploy his parachute at about 2000 feet. During the climb it became evident to the pilot that the cloud base was too low for the planned 6000 foot exit. He advised the parachutists that they would have to exit from an amended altitude of 5000 feet. There were a total of 10 parachutists on the aircraft and the two involved in this accident were the last to exit. They exited the aircraft as briefed and the video exercise commenced. This continued until the parachutist taking the video sensed that they were low. He checked his altimeter and thought it read 2500 feet but he thought they were lower so checked again and said that it read 1400 feet. He later believed that he had misread 1500 feet for 2500 feet. He signalled to the other parachutist that the free fall part of the jump was complete. The other parachutist responded with a look of surprise. He then broke away from the formation by performing a backward sommersault. The parachutist taking the video deployed his chute but he said that the other parachutist kept free falling. Witnesses on the ground said that the deceased's parachute was deployed at very low altitude and it appeared as though full line stretch (but not canopy deployment) was achieved at about the same time as he hit the ground. The nature of the injuries sustained by the deceased were consistent with hitting the ground in a feet first vertical position which was also consistent with the witness reports. Inspection of the parachute did not reveal any faults and again the inspection was consistent with the observation of the witnesses. As the descent had been recorded on video it was possible to establish elapsed times between when the prachutists left the aircraft and when certain critical events occurred. This in turn established that both parachutists initiated parachute deployment much lower than had been planned and in particular, the deceased did not initiate deployment until it was too late for his descent to be arrested. Both parachutists were wearing altimeters. The deceased's altimeter was mounted on his chest whereas the other parachutust wore his on his wrist. It was evident from the video record of the descent that the deceased did not monitor his altimeter. The deceased's altimeter was smashed when he hit the ground. The other altimeter was thoroughly checked and found to be functioning correctly. From the video it was also evident that it took some time for the parachutist who was being filmed to formate on the jumper with the camera after they left the aircraft. The parachutist operating the video camera had made about 930 jumps at the time of this accident. The deceased was making his 103rd jump.