Stroboscope photography refers to the technique of photographing a moving subject with camera’s shutter open to yield multiple stationary exposures of successive movement phases, with pulsed flash illumination or mechanical devices that intermittently allow the light passing into the camera.
A good write-up of this technique is by Professor Andrew Davidhazy of Rochester Institute of Technology titled Introduction to Digital Stroboscopic Motion photography. The article also contains a link at bottom that links to a article on film-based stroboscopic photography and details of do-it-yourself stroboscopy using a mechanical stroboscope.
The most challenging part of this technique is to get the exposure right. If each single frame has correct exposure, the overlapping parts of the photo will most likely be overexposed. As shown in the example on the left, the moving finger received much less exposure compared to the stationary hand. Having the subject in a different position for each exposure is the key to avoid this problem.
Another tip is to use a dark background and make sure the pulsed flash contributes the most exposure not ambient light.
Details on how to setup stroboscopic photography using pulsed flash vary depending on the camera and flash makes and models. For users of Nikon SB-800 AF Speedlight, you may find this article useful. Sigma EF-500 DG SUPER is compatible with many cameras and it also offers the multiple pulse flash capability.
Keywords: Digital photography, Flash photography, multi flash, stroboscope, Stroboscopic Photography, stroboscopy