High speed flash

Tip of the day:

When using your flash outside, you have to be careful: you cannot exceed your camera’s maximum flash synch speed – normally around 1/200th second. This means in bright light you cannot use a wide aperture like f/4 (which after all might mean you would need 1/800th second, say, even at 100 ISO).

But if you have a suitable external flash you can exceed that speed (the flash pulses at 30 kHz-50 kHz instead of flashing all at once).  If so, high-speed flash, or FP Flash, can be engaged on your flash.

On Nikon cameras, and on Canon cameras built after 2005, you can leave this on, and it will engage when the speed exceeds your flash sync speed, but it will not be used if not needed.

The drawback of fast flash: you get less effective power. Half at best, at smaller apertures much less. Meaning less flash range: but at least you can get outdoors portraits with large apertures.

0 thoughts on “High speed flash

  1. David Hobby at Strobist.com looked into fp mode on Nikon flashes and found that the reduced power per flash means you’re no further ahead outdoors than if you just stick with full power flash at the sync speed – it won’t allow for greater range or smaller apertures in actual use. Also most Nikons have 1/250 sync speeds not 1/200 – with a few exceptions.

  2. Craig: if that is what David said, he is wrong. I understand his point that you do not gain a lot, but you do gain the ability to go to high (low f-number) apertures.

    I do this all the time. The only time you can take an outdoor portrait at f/2.8 is by using fast flash. The catch is the aforementioned loss of effective power, so you can only use this when you are close to the subject – like in a portrait.

    True, Nikons tend to be able to be used up to 1/250th, and Canons 1/200th, but it does depend on which one (eg it is 1/300th on my 1D). Careful when using Pocketwizards and strobes: you’ll be lucky if you get close!

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