As Mr Gong explains:
Filming in North Korea is a bit of an iffy task, and you never know when a minder may decide to confiscate your memory cards or camera. That was a risk I didn't want to take, so I decided not to reveal to them the fact that my 5D was capable of shooting video. I taped up the back screen with black electrical tape.
Because I shot with Nikon lenses by way of a simple adapter, I also lost any form of autofocus. Moreover, to be truly covert, it was a good idea to manually focus without looking through the viewfinder anyway.
For a few weeks before my trip, I'd practice every day, shooting with the camera around my neck, manually focussing and composing blindfolded.
It worked, and I was able to successfully bring all the footage back. And the [funny] thing is, the military officer who was supposed to go through every single picture on my camera didn't even show up.
What you'll never believe is just how beautiful North Korea looks, how warm and welcoming the people seem to be and how nice their subway stations look like.