When shooting with Strobes, in most Cases the Shutter of the DSLR is set to Sync-Speed.
Sync-Speed is the shortest possible Shutter Setting, where both Curtains are still open, so the whole Sensor (or Film) is exposed to the incoming Light.
Usually it is around 1/200 s depending on the Camera Model. At 1/200 s fast moving Objects will be blury. Watersplashes, or like in this case flying Powder would not be sharp when shooting with ambient Light.
To freeze the Action you will have to deal with short Flash Durations. Short means at least 1/5000 s and shorter. Strobes like „Einsteins“ or other Monolights can reach Flash Durations of 1/20.000 s. Simple Speedlights can reach that short Flash Duration too, when set to lower Power like 1/16th or 1/32nd of max Power. Sometimes, 1/32nd of max Power might be not enough Light, so you have to increase ISO, or open the Aperture. But by opening the Aperture you are risking a shallower Depth of Field, which in most Cases, when shooting with a Macro Lens, is a huge Disadvantage.
So here is a Shot of two Cosmetic Powder Brushes. It is a 3-Lighting-Setup. Two Elinchrom ELC HD-500 at 1/5000 s at t0.5 on each Side, slightly from behind. Attached to the strobes is a Stripbox.
Because of the semi-glossy Surface of the Cosmetic Brush and the cylindrical Shape, it is necessary to create a Gradient. To achieve this, a Diffusor is set on a shallow Angle in front of the right Stripbox. The third Light highlights the Hair of the Brushes. It is created with a Snoot on a Speedlight.
