USE HIGH SPEED SYNC

Capture pin-sharp action or shallow focus using flash and fast shutter speeds

If you are shooting in a studio with your subject framed against a seamless background, you probably won’t need to use high-speed sync (HSS) flash mode. That’s because you can easily keep your shutter speed below the maximum flash sync speed, by stopping down your lens to f/11 or smaller.

However, if you are shooting outdoors with an ultra-bright lens such as an 85mm f/1.4, and want to throw the background out of focus, there is an additional challenge. At these settings in full sun, even at the base ISO of 100 or 200, it will be almost impossible to limit the exposure duration to shorter than around 1/200sec.

Once these settings are exceeded, the image will become unevenly exposed, due to the imperfectly aligned timing of the shutter movement and the flash duration. On some cameras, or with certain flash triggers, the flash may not fire at all, or the image will be overexposed. With HSS mode, it is possible to increase the shutter speed all the way up to the maximum (approximately 1/8000sec).

This works by emitting an extremely highfrequency pulse of light, covering the whole flash duration, providing even exposures. However, this does have a trade-off in power output, so it is necessary to limit flash-subject distance or add another flash to compensate.

HSS mode works by emitting a high-frequency pulse of light, providing an even exposure