A pleasant Easter weekend arrived with me ‘volunteering’ to help Steve Sherlock excavate a round house constructed in 2005, which burnt down 3 days later at Kirkleatham Hall, Redcar.
With the passing of 12 years it was an idea that excavating the modern destruction of the roundhouse, with the full knowledge of its original construction techniques may offer some element of comparative analysis in the destruction of excavated real round houses.
My role, as well as getting roped in to scrape muck was to provide a overhead timelapse video record of the excavation over the four days, that would be edited to give us a 10 to 15 min time lapse video of the whole excavation.
To film this event, I used a standard 7m telescopic alluminium mast used by radio amateurs which was guyed at the top, a cheap and cheerful bit of kit, this system was used at the Newsham excavations in 2015, and despite heavy winds on most days provided a stable platform for filming.
I used a Go Pro Hero 5 to film the event with a large memory card to allow hours of filming. These cameras are outstanding bits of kit, with image resolution upto 4k, providing imagery that is the same if not better than most DSLR cameras. They are waterproof. and can be used under water if it takes your fancy. They are effectively the hi-spec image capturing device and circuitry of a top spec DSLR, without all the lens, heavy case and ancillary functionality needed for normal camera work. The GoPro has both Wi-Fi and Bluetooth functionality, and all functions can be controlled remotely by a phone or tablet whilst in operation on the top of the mast.
The camera was attached to the mast using one of the array of clamps from a clamp kit available on ebay for a modest price.
The only addition to the standard kit that was required was jury rigging some sort of external power for the camera. The battery in the camera will probably run for 1.5 to 2 hrs before requiring recharging. The impracticalities of dropping the mast several times a day, losing the framing, and the best part of 30 mins filming each time was impractical. I therefore used a cheap 12v to 5v USB converter off EBay to do the job, added a length of 5 amp 2 core lighting flex to the length of your mast, and at the bottom, connected it to a LIthium Polymer (LiPo) 3s 10.8 v battery used by drones, and which are readily available on Ebay. The 10.8v voltage is dropped by the USB converter to the 5v which the Go Pro needs, one charged LiPo ran the GoPro for the whole 4 day excavation without recharge.
Video normally runs at 30 frames a second. To get the time lapse effect of speeded up motion, we take images at less than 30 frames a second and then play them back at 30 frames a second (This is all done by the GoPro, so nothing complicated.
The rule of thumb for time lapse is if there is visible movement in your scene then set the timelapse to between 1-3 frames per second, this will allow somebody to walk across a scene, with the viewer seeing the full movement of their gait, higher frames per second will see them effectively jump from one place to another. Non perceptible movement such as the sky at night or a flower opening will require much longer frames per second times.
For the purposes of this excavation we used 1 frame per second, which effectively reduced the recording time to 1/30th of the 6 hrs per day we were excavating, which when run at 30 frames a second takes 12 minutes to view. With the removal of lunch breaks , tea breaks etc, we are hoping to condense the whole 24hrs of excavation into a watchable 10 to 15mins.
This is hot off the press, I will add some of the time lapsed video, and links to the kit we used later.