Friday, September 4, 2009

Canon's High Speed Sync

Not long ago, Mr.McNally blogged about High Speed Portraiture. That post co-incidently followed a quick shoot I did using Canon's High Speed Sync (HSS) of the lovely couple below.
Scott & Amanda
For this shot, I had to concern myself with:
a) Not blowing out the background on a bright morning.
b) Not seeing too much detail in the background.

To get a nice balance ended up at ISO 100, f/3.5 (for blurry background), and 1/800th (for no blown highlights)... Beyond normal flash sync speed.

Luckily, I've got a nice 3 metre (9 foot) home made OC-E3 (off camera cord) for my 580EXII, so I could get that off camera, in a nice cross-lighting position... by turning on the HSS feature (it's just a button on the back of the 580EXII that has a lightning bolt next to an 'H'), I bumped up to full power, bounced into a reflective brolley, moved in as close as it needed to be to still be out of shot, and pumping out enough light to get a nice exposure.

Why full power? As Joe mentioned, the downside of high speed sync is a big loss of flash power. And when you bounce into a brolley, you lose even more.

Gotta love long off camera cords a.k.a. strobe on a rope.

Also good for the occasional dramatic sunset
Graduation

3 comments:

  1. I'm a bit confused, you mention you used HSS, which would imply that you are using ETTL via the long sync cord, but you also mention that you were shooting at full power which would imply that you are in manual mode (1/1). What am I missing ?

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  2. Sorry for the slow reply, but here goes...
    it is possible to set the flash power to manual, and also switch on HSS.

    The ST-E2 won't let you do it, but if you have the flash on camera, on on the end of an OC-E3 cord, you can do it.

    Having a 580EXII 'on camera' (on the end of a 1m cord) allows me from the 40D to switch (from the camera menus) the master and all slaves between ETTL and Manual, and control their power!

    In fact, this is my biggest gripe with the ST-E2, its such a pain to set the flashes to manual mode (it can be done with limited success by putting a 580EXII on camera, setting the flashes to manual, then taking off the 580EXII and putting on the ST-E2.

    Hope that helps.

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