This photograph is another from the Mangyongdae Schoolchildren's Palace and was also taken in a class where children were being taught to play the kayagum.
I managed to swap lenses between classrooms (I was being rushed from one to the other) so I took this one with my 24-120 mm lens (focal length was 75 mm). The f5.6 aperture enabled me to achieve just the right DOF to keep the girl in the middle, who glanced up at the camera for a moment, sharply in focus, but the other two girls in the foreground and background slightly out of focus.
I used only the in-camera flash for all my North Korea shots (I didn’t take my external flash because I thought that looked too ‘professional’ and might make my guides nervous) so the original was quite under-exposed. I cropped, adjusted levels and increased brightness, but this left the photograph rather noisy. I then used Neat Image to remove about 70% of the noise (I tried the default setting at 100% but this left the faces looking artificially smooth), partly sharpened in Neat Image and then applied USM in Photoshop.