What’s this Hi-Speed flash thing again?

A reminder for all you speedlighters.

Say you want a shot like this, taken a few days ago,with your Nikon D90 or whatever SLR you have equipped with an external flash (like an SB900):

Yes, direct on-camera flash, when used outside and hence mixed with available light, can give you this – not bad eh? And the picture isn’t bad either. 🙂

But look at the background. It is blurry.

That means a large aperture was used (f/5.0 in this case).

But that means the shutter speed must have been very fast – even at low ISO, you need a fast shutter on a sunny day if you want the aperture to be large. I used 1/2500th second.

But hang on. When using flash, you cannot exceed the flash sync speed! Which is 1/200th second on this camera.

So how did I do this? I enabled “fast flash”. (“Auto FP flash” is what Nikon calls it; Canon calls it “High Speed flash”). On a Nikon, go into the flash part of the pencil menu and find flash sync speed, and set to Auto FP. On a Canon flash, indicate the little “H with a lightning symbol”.

Now the flash, whenever you exceed the sync speed, pulses rapidly instead of firing all at once, meaning that you can shoot at fast shutter speeds, where the shutter never fully opens all at once.

The drawback is that most power is lost, so you need to be very close. Aim the flash forward and watch the indicated flash range: as soon as you exceed the sync speed, that range drops rapidly. Stay within that range and you get great outdoors flash pictures!


NOTE: Come join me for a five day workshop at August’s Niagara School of Imaging – it is filling up but there is still space. Act now and spend five days with me on all this stuff, and emerge a flash pro.


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