I won’t be going into too much detail about why using flash duration to stop motion is impractical, and in most cases even impossible, as I have already done that in my previous post, which you can find here. Instead, and in response to an email I received a few days ago, I decided to make a quick video, which explains and shows why flash duration is an inferior tool for freezing motion, compared to shutter speed. In my demo I am using the new PRIOLITE ULTRA, which is available for $799 during the pre-order offer at PRIOLITEULTRA.COM, but any PRIOLITE HotSync strobe currently available at shop.priolite.us will give you similar results in terms of high speed flash sync and stopping abilities.
Relying on flash duration to freeze motion (and prevent motion blur), is like relying on more horsepower when maneuvering inside a parking garage: it won’t make a difference. Unless you are shooting in absolute darkness with no ambient light contributing to your exposure (e.g. closed down aperture, or dark room), the stopping power of your strobe is irrelevant. Let’s say you are shooting with a closed down aperture to block out ambient light, you likely need more power on your strobes to “punch” through the smaller aperture as well, but then the flash duration on your strobe isn’t really that fast anymore (often less than 1/2000th), making this again an inferior solution to using shutter speed instead. The ability to synchronize at up to 1/8000th of a second to all of PRIOLITE’s HotSync strobes AT ANY POWER SETTING illustrates how the stopping power of the strobe is completely irrelevant, and a benchmark you should not rely on when picking your next monolight or pack/head (as long as your new lights support HotSync).
In fact, strobes that rely on stopping power are useless when it comes to true high speed flash sync on focal plane shutter cameras, because they are too fast, or not powerful enough to put out sufficient light over a long enough period, so that the entire sensor area is covered, while the shutter moves across the area. If you are using leaf shutter lenses, then flash duration matters, but not for freezing motion at higher shutter speeds, but rather to make sure the entire charge is depleted during the exposure. Different shutter technology, different needs.
If you want to have the freedom to balance ambient and flash light, prevent motion blur or freeze motion at any shutter speed up to 1/8000th on most Nikon, Canon, Sony, and Pentax cameras (645z and 645d can go up to 1/4000th), and do so AT ANY POWER SETTING of the strobe, then PRIOLITE HotSync is the only solution today that allows you to do all of this automatically, with no need for manual adjustments (other than the power output you want from the strobe). PRIOLITE ULTRA makes this even easier, because it is so small, that you can take a powerful 500Ws monolight with you to more places than ever before, and its metal body, metal frame, metal hardware, universal metal mount, built-in 2.4GHz wireless, Li-Ion battery, 2-year warranty, easy-to use design makes ULTRA the superior solution for photographers on the go.
If you are used to natural light shooting, imagine the possibilities: instead of creating your images around the available light, create the light around your images!