project 2

Use HSS mode for better fill-flash portraits in daylight with Peter Travers

Use HSS flash mode for better fill-flash portraits in daylight

it’s great to use a little fill-flash when taking portraits in daylight to lighten up people’s faces and reduce harsh shadows. However, DSLRS have a maximum flash sync speed determined by the amount of time it takes for the shutter curtains to physically move across the sensor – usually 1/200 or 1/250 sec, depending on your EOS DSLR. This means that, in bright conditions, you can’t shoot with flash at wide apertures at these sync speeds (eg f/2.8 at 1/200 sec) without ending up with overexposed images, and if you set a faster shutter speed, you’ll end up with a dark band across the frame as the moving shutter is captured in the image. An alternative option is to set a narrower aperture, but while the face will be brightly lit with the flash, the background behind the subject will be distractingly sharp.

What you need is a flashgun with a High Speed Sync (HSS) mode (all eight flashguns in last issue’s Super Test have this mode). HSS fires a pulse of low-power flashes for the duration of the exposure, rather than a single high-power burst, enabling you to set a much faster shutter speed than normal. This means you can open your aperture to blur your background for more dramatic portraits, because you can choose a higher shutter speed in daylight – such as f/2.8 at 1/1000 sec.

Another bonus of using HSS and faster shutter speeds is it can capture action portraits without a hint of motion blur in subjects.