The high speed photography of ballistic experiments by means of a Cranz-Schardin Camera would very often require a multiple time scale spark controller. In the model described hereafter, the digitally adjusted time interval between two successive frames is kept constant within a group of 4 frames, but can be different in the other groups. As an additional feature a Velocity Dependent Delay ensures a precise triggering of the camera. For instance, the first frame can be synchronized with the impact, regardless of the velocity of the projectile.
"Improvement Of A Cranz-Schardin Camera", Proc. SPIE 0189, 13th Intl Congress on High Speed Photography and Photonics, (27 July 1979); doi: 10.1117/12.957547; https://doi.org/10.1117/12.957547