Thursday, July 29, 2010

High Speed Sync

Digital photography in itself offers many new possibilities for photographers that film users never had. The simple ability to review an image immediately after taking it has revolutionized photography. The learning  process has become exponentially quicker.

Other new advances in technology offer the possibility to break new ground in imagery. With new technologies like “High Speed Sync” flash users have another new creative outlet. I would even suggest users have the chance to create images never before conceived. It’s a very exciting time.

Not to long ago flash exposure was limited or constrained by a shutter speed of about 1/60 a second or so. On some systems you might be able to go to 1/250 of a second. The flash fired when the shutter was full open, when the film or sensor was fully exposed. This is commonly known as X-sync. We were very limited to a slow shutter speed but not any more.

These days using High Speed Sync flash we can use our flash at speeds such as 1/6000 or 1/8000 of a second. Rather than firing once the flash strobes, synchronized with the shutter opening. In this case only part of the sensor or film is exposed, a slit, the flash strobes to ensure a consistent exposure throughout the frame. There is a trade off here, the faster the shutter speed the more the flash has to strobe to ensure exposure throughout the frame resulting in a reduced effective range. Following is one example of my use of HSS flash.

Anatomy of a street portrait, flash at 1/6000 second.

“Steve” is a busker who plays classical guitar in the streets of downtown St John’s Newfoundland Canada. When I decided to photograph Steve the first thing I had to consider was that he looks down a lot which meant that if I wanted to capture his face I had to get on the ground, yeah lay on the sidewalk downtown during a busy lunch hour. :-(

This meant I had to use the sky as a backdrop. So I (in camera) metered at the chosen aperture (f5.6) and had to go all the way to a shutter speed of 1/6000 of a second in order to keep the sky. My camera was set at iso200 and I was using of camera flash with a homemade diffuser

I must say I am very happy with the exposure and love all the diverging lines. It was worth taking the chance of being stepped on. :-)

Yeah it’s a very exciting time indeed.