By Technical Editor Matt Allard:
Japanese amateur astrophysicist, Keisuke Iwaya has sent various cameras up to space using meteorological balloons to capture images of earth. On 20th of July, 2014, he sent a Blackmagic Pocket Cinema Camera up for the first time. The BMPCC was housed in a special casing slung below a weather balloon.
The camera was set to record to an Atomos Ninja Star recorder equipped with a 128GB CFAST card. The journey took two hours to go from the ground to the 28.5km (17.7mile) peak of the stratosphere.
The”Fusen Ucyu Project” (which translates to Balloon Space) required lots of precise calculations and pre testing. The team needed to work out what ISO, shutter speed and f-stop the camera needed to be set at to correctly expose from space. Weight was also a big factor as the housing attached to the balloon could hold a maximum of 1Kg. Initiall trials were done with a Nikon D7100 DSLR and Sigma 10-20mm f3.5 lens, but the combination was deemed to be too heavy and eventually the decision to go with a BMPCC was made.
The BMPCC combination met the weight requirement but the team had to solve a few other problems to make it work. They used a Panasonic 7-14mm f4 lens to get as wide as they could on the BMPCC. Fitting a fixed ND filter to this lens proved to be tricky. By cutting out the middle of the lens cap and inserting a Kenko Pro1 Digital ND16 Wide filter they were able to find a solution that worked.
Keeping the BMPCC powered up for two hours was the next problem that had to be solved. Because weight was an issue the team found a battery plate solution that used the same type of NP-F batteries that also power the Ninja Star.
In space things are remarkably bright. The Kenko Pro1 Digital ND16 Wide filter was the widest they could find that would work. The team said it would have been better to use a stronger filter but they couldn’t find one to fit. They chose not to use multiple filters as the condensation build up in temperatures that range between -60c and 20c would have been a problem. The resulting exposure with the BMPCC was f 16 and 1/60th shutter at ISO 800, 24fps.
Going into space was going to push the camera to its absolute limits. The BMPCC is only rated to work in temperatures between 0-40c. The camera also had to free fall for 30 minutes and then survive the impact once it came back to earth. The team designed several features that enabled all the equipment to return intact and operational.
The Fusen Ucyu had special permission from authorities to send the balloon and camera up into space. Please do not attempt to try and do this yourself at home.
All photos courtesy of Raitank.