Indeed, you are correct, so long as the flash is over-powering any ambient light, the duration of the flash will no doubt determine how well the motion is frozen. Since I’m in a mood to write, here as some other thoughts on the subject. Depending on how you setup your shot, the freezing of motion can be a combination of all three variables you mentioned above: flash duration, shutter speed, and the strength of the ambient light.

*If you’re shooting in bright sunlight, you can freeze motion with a high shutter speed without any flash.

*If you’re shooting in low light with a flash with a short flash duration (as Chase did for the article/video you mentioned, and as we did here) then you can use a low shutter speed (needed because many DSLRs don’t sync over 1/250 to do the shot like taking a normal photo), and a flash with a short flash duration to freeze the motion. This method is the classical method, developed by the late Dr. Harold Eugene Edgerton. It’s very useful for stopping bullets in mid-air and exploding glasses.

*In this shot, the strobe setup was overpowering the ambient, so the exposure of the image was determined by the flashes lighting the entire subject with an Octabox, and since we wanted to see how fast we could sync the RX system to the LX3, it made sense to use a high shutter speed in combination with a short flash duration. The shutter speed could have really been anything between 1/60 and 1/1000 with similar results. By using a short flash duration strobe, we were able to freeze the coffee in the air as desired without going through all the setup hassle of the Chase article/video.

As mentioned in the article above, one reason for using the Elinchrom Ranger RX system was that, “With such a short flash duration, you can freeze moving liquids with super precision.” And one reason for using a camera like the LX3 with Skyport triggers, is that you can easily sync up to 1/1000 sec. This is highly useful when using flashes in environments with high levels of ambient lighting, like in the sunshine where you might want to have a high shutter speed (say 1/600 to expose for the environment) and still be able to trigger your strobes.

In this setup, we were just hooking up the Skyport to the LX3 and shooting. Much less complicated than the setup Chase used, which involved setting his Hassy up on a tripod, opening the shutter (the Hassy can’t sync with the flash at the required speed to freeze motion in that setup), and then triggering the strobes separately. We could have done it this way, but sometimes it’s more fun to think outside the Chase.

I edited the article to make the influence of short flash duration more clear.

-Mark