Continous light is widely used for bullet-time installations but this comes with a few issues that can become quite a headache to solve. Continuous light is either daylight, led panels or complex light designs
As always, having proper hardware is the first step toward quality results. In USB, always work with powered USB hubs and quality usb cables (check out the suggested gear here: https://xanglecs.com/gear). In a networked architecture (Raspberry Pis), make sure you're running on a gigabit connection.
What's important here is to find the right balance between sharpness and shutter lag. The slower the shutter, the more blur you'll get. The faster the shutter, the more imprecision you're going to induce. The sweet spot is around 1/200s. Depending on your camera model, you might have to go a bit slower at 1/160s, or you might be able to push to 1/320s. From our experience, 1/320s is the very limit.
One trick to make the shutter glitches less visible is to go in interval mode instead of trying to freeze the moment. Start with an interval of 1ms, and move your way up to find what's working properly with your installation.
If you need absolute precision, the use of strobe might be a better option. More details here: Constant lights vs strobes
- It is possible to get really nice results with continuous light even with tons of cameras, even on old / beaten up ones: https://www.instagram.com/p/Bz9Yw-FhxCF/
- For very fast-moving objects (a swinging ball on a rope for example), there is absolutely no way to freeze using continuous light. The mechanical shutter is simply not precise enough for this. Go with strobes / flashes in these cases.
Flickering is induced by lazy shutter problems. This becomes more obvious over time as your cameras become older. The faster you set your exposure time, the more you get flickering. The way to reduce it is to go at a shutter speed of about 1/160s. If one specific camera seems to be always brighter than the other, you might have to switch it for another one.
More details about flickering: How to avoid flickering