Tuesday, May 29, 2012
How to use high-speed flash sync for creative effects
|This Article Features Photo Zoom|
I still remember the day I first used high-speed sync flash. I was shooting mountain bikers on desert slickrock in Moab, Utah, and I was having a bad day. I was frustrated about getting motion blur every time I took a shot and used flash. Motion blur looked nice on some images, but I wanted a razor-sharp image. I also needed to add some fill-flash to the rider's face since his helmet visor was creating a shadow.
Digital camera technology changes as fast as the stock market. Every month there seems to be new camera technology or postprocessing techniques that open up new doors in photography. Think about it—HD video capture, ISO 204,800, mirrorless cameras, wireless shooting, iPad compatibility—photography is evolving quickly.
High-speed flash photography fits in this category. First, there was High Speed Sync photography, allowing speedlight shooters the ability to shoot much faster than the standard 1⁄250 sec. flash sync speed. But then HyperSync was introduced, and now photographers could use studio flash packs at speeds of up to 1⁄8000 sec. Incredible!
Why all the excitement about high-speed flash photography? Most photographers assume this technology allows you to use flash on fast-moving subjects and freeze the action. This is true, but only the tip of the iceberg! There are many benefits of high-speed flash photography, and every photographer should know how to use it.
FLASH SYNC BASICS
Every camera has a shutter sync speed, the maximum shutter speed the camera can use with flash. For many cameras, this is 1⁄250 sec., but it can be slightly faster or slower depending on the camera. What happens if you use flash and shoot faster than the sync speed?
Cameras have two shutter curtains moving in conjunction with one another during an exposure. If your exposure is 1⁄250 sec. or slower, the shutter curtains don't overlap—one is retracted while the other is moving. But if you shoot faster than 1⁄250 sec. (assuming this is the sync speed), the rear curtain starts to close before the front curtain has fully opened. If a flash is shot during this exposure, part of the scene will be blocked from the flash illumination. The result is a dark band across part of your image. For years, this meant you couldn't shoot faster than 1⁄250 sec. if you wanted to use flash. Then High Speed Sync flash photography was introduced.
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