New Perspectives - Aerial Images
- Category: Blog Filming and Video
- Published: Monday, 10 March 2014 15:04
The world from above
Looking for new perspectives to show the world from angles that are not easily available we decided to add a copter to our filming and photography gear. Aerial images give the viewer an unexpected and spectacular point of view. When we started our first flights over our home we were surprised to discover how much more beautiful and interesting our location is when seen from above. Now we can figure out even better how our surroundings are arranged in space.
But - yes there is always a but - spectacular images are often not easy to capture. The advanced techniques of the digital era bring the filming/photography possibilities to a new dimension but at the same time require new technical skills from the operators of the cameras.
For aerial shots you need some skills and the proper gear. In this blog I will try to give a short overview over the necessary gear we are using. The part with the flying skills will follow in a next blog because we are ourselves novices in this field. We had barely three days of practice just to find out that the film sequences were jerky, had a lot of annoying rolling shutter or, even worse, were partly not recorded.
For taking aerial shots you need first the knowledge of how to assemble the whole complex aerial gear, including the copter, transmitter and receiver of the radio signal and the stabilizing of the camera. Those with a master degree in physics and electronics are obvious in advantage.
Our two-person-team luckily comprises of me, an ambitious film girl who absolutely wanted to take aerial shots and of my husband, who is the brain in the house. Which means that after several weeks (interrupted by some travels) of trying and late night work Claus proudly presented me a hexacopter ready to fly.
The next step is to fly the copter and to control the camera - ideally at the same time. Which sounded very easy until we started our first test flights. Our very first flight ended with the copter in our cherry tree. That was the moment when Claus decided to build a completely new and more stable copter which suited best our needs. Because we travel extensively to remote areas where a compact equipment is of utmost importance we wanted a light copter. The air transportation and our motorcycle adventures require a small device easy to transport. After searching the internet for a solution Claus decided to assemble a copter by himself, a trade off between weight, dimensions and flight stability. Also we didn't want to use a GoPro camera which come along with most of the ready-made solutions on the internet. The viewer gets quickly tired of this GoPro fish eye perspective. Of course there are also very expensive alternatives for the big, professional cameras. But they are costly and heavy and difficult to transport.
So here is the assembly of our DIY Hexacopter (whereas this DIY sounds very ironically to me as I would never be able to do myself such a thing). Considering the price and the dimensions the copter turned out to be very stable and efficient during the flight.
A very compact hexacopter, foldable and it even fits in a suitcase!
- the carbon fibre frame from Carbon Core 650, which means there are 6 motors arranged in a 65 cm circle - that makes the copter a hexacopter (Carbon Core Website)
- the 3508 motors from Tiger Motors (T Motors) are of high quality with Japanese bearings. All six motors have a thrust of 7.2 Kg including the copter weight. So it makes sense to keep the payload as light as possible to gain more flight time (the flight time increases overproportionately with the reduction of the payload).
- 6 motor controllers with 40 amperes from Tiger Motors
- Carbon fibre propeller from Tiger Motors (12 x 4 inches)
- the leg set is shortened by Claus. He attached foldable extensions for a better transportation
- what is very important for us: the whole Copter is foldable: four arms can be hinged at the middle - that is easily done by wheel bolts
- a flight controller from DJI Wookong (DJI Products) with GPS Hold, "Coming Home" automatic and POI (point of interest) automatic - the copter will fly around a marked object
- a receiver from Graupner GR24 and a radio transmitter also from Graupner HOTT System (Graupner Products)
- a display for voltage control
- four LiPo batteries from Desire 4S (14,8 V and 6600 mAh which make 98 WH/ Watt per hour and is within the limit of the Dangerous Goods Regulation for Aircraft Transportation)
- the mount of the camera: a brushless gimbal originally from China but the board was not functioning properly so Claus replaced it with an original Alex Moss board (flyduino.net). Its software BGC 2.4 (Basecam Electronics) allows the fine calibration of the gimbal on a computer The carbon fibre frame was initially very tensed up producing sudden jerky movements during the flight. Claus decided to built an open frame of aluminium fitting a Panasonic GM1. The Graupner transmitter can control also the pitch and roll axis of the gimbal. Claus assembled it that way that the gimbal can point the camera even vertically down (90 degrees).
- the camera is used mainly for filming: the Panasonic GM1 has a good image quality for the price and dimensions. Its good reviews convinced us to film with the GM1 (Review on EOSHD). After we flew our first test last week we found out that the sequences had a bad rolling shutter and from time to time some jerky movements. The movements we removed by the new, open gimbal but it took us some hours of analysis and trying around until we found out what the cause of the rolling shutter is. Initially we used the zoom kit lens 12-32mm with a build in stabilizer. This means that the inner lenses are very light and loosely fitted in a cardan shaft. In certain flight situations, especially during the take-off the lenses start to oscillate (and they won't stop oscillating during the whole flight)and cause an annoying rolling shutter. After replacing the lens with a pancake 14mm from Panasonic the effect was gone.
When filming movements, like during a flight, is best to shoot in progressive mode. We found out that the GM1 is shooting only 24fps progressive. The 25 fps setting is delivering actually a 50i fps sequence with ugly combing effects along the lines in the image (like at 03:20 in the test clip).
The Wifi function of the GM1 would have been great for controlling the camera with an IPad (start and stop of the recording, focussing etc.) and having an image returned to our device. But the range of the WiFi is very short and if there is no connection to the Ipad the camera crashes.The whole record is deleted for some unknown reason from the SD card.
Therefore for the moment we are flying "blind" without seeing what exactly the camera records. Our next project will be the use of goggles to have a video image returned.
On our travel beyond the Arctic Circle in Norway we will practice more with our hexacopter. Stay tuned for our next blog about our flight experiences in an unknown environment.
Until then watch out test flights over the house which succeeded without crashes:
For licensing our awesome landscape aerials please follow the link below: