Expat Kiwi, Denis Smith, explains how he does it in this video interview. Like the other images on his "Ball of Light" web page, the backstory is also very compelling: reaching a mid-life crisis while working for Fuji Xerox and purchasing his first camera less than two years ago.
Although he is likely unaware of it, Smith is actually imaging a fundamental theorem of Lie groups:
The coset G / H of a continuous Lie group G by a closed subgroup H is a manifold of dimension given by dim(G) − dim(H).Here, G = SO(3) is the special orthogonal group of norm-preserving continuous rotations about an origin in 3-space with the subgroup H = SO(2) corresponding to rotations in the plane. The topology of SO(3) in Euclidean space is a solid ball with dimensionality given by the number of Lie group generators. Since SO(n) has n(n−1)/2 generators (e.g., 3 Euler angles when n = 3), it follows that the corresponding coset manifold is
which is the 2-sphere approximated in the above photo.
From the standpoint of Lie groups, "Sphere of Light" would be a more accurate name for Smith's project.