A few days ago we showed you a way to freeze subjects in ice in Photoshop. Now it’s time to freeze their motion in front of the camera, with the assistance of a little flash. And, of course, a little help from Jay P Morgan of The Slanted Lens. In this video, he shows us how we can freeze the motion of a dancer with strobes.
The principle is quite simple, when your camera settings are killing all of the ambient light, your exposure is defined by your flash duration, not your shutter speed. Flash duration is the amount of time the light is putting out more than a certain amount of light. The shorter the flash duration, the faster your exposure.
Depending on the type of flash being used, duration of the flash can be altered. Essentially, it cuts the light’s output early. This has the obvious effect of reducing the amount of power that it can cut out, but when you need to freeze motion, that’s something you have to figure out how to deal with. With speedlights, it can often leave you lacking. But now many studio strobes use similar technology.
The Dynalite Baja strobes that Jay P uses have this ability. And this feature is one of the reasons I went with the Godox AD360II strobes for use on location. But these aren’t the only two units out there that do this these days. If in doubt, check your manual, or tweet your strobe manufacturer and ask.
If you’re mixing high-speed flash – that’s what we’re doing here, which is different to high-speed sync – with ambient, you’ve got potential issues. If the ambient light is going to put light on your subject, then even though some parts will be sharp, other areas will be blurred. You can get around this by simply speeding up your shutter to kill all of the ambient light. Or, you can use it creatively by combining the blur with intent. Personally, I’d suggest going rear curtain sync if you’re going to do this.
You can do this with speedlights, you just might have to bump up your ISO a bit, and it may be more difficult to compete with ambient light, especially if you want to use a softbox (even quite a small one). Simply because they lack the power. But if speedlights are what you have, then they’re a great way to experiment with the technique using gear you already have. Then you can decide if it’s worth investing in something more powerful.
But you can use these principles to freeze just about anything. I’ve done it with hummingbirds around a feeder before now using a couple of SB-900s at minimum power. Works a treat.