Canon 580Ex Flash Duration

I was curious as to what I could freeze using my Canon 580Ex flashgun so I had a play in the lab using a photodiode and scope to measure the flash duration of the flashgun (averaged value over 4 flashes) at the various power output settings. The results were:

1/1 power = 1/1000 second
1/2 power = 1/2000
1/4 power = 1/4000
1/8 power = 1/9000
1/16 power = 1/15000
1/32 power = 1/21000
1/64 power = 1/30000
1/128 power = 1/35000

“What does this mean” I hear you scream, closely followed by “wtf has this to do with photography”?

Well the answer is, in order to freeze the movement of a fast moving subject a photographer will, at first, try to freeze the movement using a fast shutter speed. The maximum shutter speed on a good DSLR is around 1/8000 second but in order to use this speed you either need:

very, very strong lighting,
a wide open aperture and/or
a high ISO setting

An alternative is to use a flashgun(s) and by reducing the power output of the flashgun the flash durations can be as short as 1/35000 second for the 580Ex flashgun. If the flash is placed very close to the subject a small aperture and low ISO setting can also be used.

Various experiments with High Speed Flash can be viewed here

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20 Responses to Canon 580Ex Flash Duration

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  2. Michael Sherrard says:

    What mode was your flash in? (Manual I assume.) The HSS mode shoots out a series of less powerful flashes which allows you to use the shutter. I would like to see the intensity compared with your results. The Manual mode (which is the mode you used) puts out a flash which can shortened, either with ETTL or with a smaller power. (It is interesting that it is not the flash intensity which changes, but it duration.) Then there is the Multi (strobe function) which is still a bit of a mystery to me. My first experiments with it using a single flash in Multi is that it is MUCH more powerful than the flash you get in manual, but I would love to see you do the same experiment with the Multi mode and a single flash. I would also like to see how the intensity/duration of the Multi flash changes with power.

    • photosbykev says:

      The guns are always in manual mode and using the power control the flash duration is reduced by a thyistor control that quenches the full power flash early. Using High sync mode or multimode the flashgun emits short pulses of flash. The HSS modes will produce a stroboscopic effect on the droplets and each pulse is relatively low power, in Multi burst mode the highest flash frequency is 10hZ i.e. 10 flashes per second and as I’m timing a collision to the nearest one millisecond and the event only lasts a few milliseconds multiflash isn’t of any use to me.

      regards
      Kev

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  5. Terry says:

    There’s one more trick you can use.

    If you use a fast wide angle lens, you can use a relatively larger f/stop and still have pretty good depth of field. That lets you use a lower power/faster flash setting, have enough DOF and get better stoppage of action.

    I shoot Canon gear, but I recall reading that the old 8 mm Nikon did not have a focusing ring because the DOF was effectively total. They demo’d this by putting one of those colorful South American tree frogs on the objective of the lens on a camera laying lens-up.

    • photosbykev says:

      When shooting water droplets the DoF is always an issue because most people will use a macro lens with a focal length around 100mm to give a reasonable standoff, using a wide angle lens with a much shorter standoff to maintain the magnification doesn’t alter the DoF it just gets your lens wet :)

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  9. mick says:

    Hi i have 5d body and want to do some high speed shots. Im after nature shots birds, bats, insects in flight etc. Im experimenting with 430 ez and 100-400 is lens , with the canon lc2 remote in infra red beam break mode.This is an old bit of kit but canon have not replaced the beam break mode on any other remotes since. I have worked out how to disable the auto power off on the camera and flash.To connect the lc2 to the 5d via the n3 lead i am using the canon remote switch adapter ran3. So far the beam break is working and flash is firing.I need high speed shots and have the 430 ez in manual mode in high speed flash with the camera in manual using shutter speeds of 800 sec at f22 this is lighting a subject around about 1.8 meters away with a weakish light. The speedlite is set at 1/1 power i also have a canon 300ez on the hama optical slave wich is operating and throwing some light onto the subject. Quite how that is working i dont know i thought the pre flash from the 480 would trip the slave to soon,I dont know if 300ez can be prevented from sleeping its no use at the moment. Any ideas or advice would be very welcome.
    many thanks Mick

    • photosbykev says:

      Hi Mick,
      using the speedlite at 1/1 power will give a flash duration of around 1/1000 second but using it in HSS mode will pulse the flash for the duration of the 1/800second exposure and given out a lot less than full power. I’m guessing this setup is being used in daylight hence the need for a fast shutter speed. It is possible to use an external shutter mounted on the lens and synced to the flash, this type of shutter is typically 1/400 second and would allow the flash to be used in normal mode. If it is in darkness then shutter speed can be much longer and you could turn off the HSS which would give a more powerful flash. I would be tempted to open the aperture slightly to f16, at f22 the 100-400 lens quality falls off, you would loose some DoF but the quality would improve and you have another stop of light to play with. I haven’t played with the 300ez but it maybe possible to make a small circuit to pulse the flash just inside it’s timeout period, a simple 555 timer circuit could do this.

      best regards
      Kev

  10. Steve says:

    This is great, will have a go later on. Did you use coloured water?

  11. Nikki says:

    thanks for the reply! I figured it out while shooting =P

    http://farm4.static.flickr.com/3640/3432729657_1534fd33b3_b.jpg

    my image =)

  12. Nikki says:

    Your balloon image is beautiful =) I am planning to attempt something like this for a photo class of mine and I am just wondering how you actually broke the balloon. I will be using a microphone-triggered flash system (not as high-tech as yours but it should do the job) I was thinking maybe a pin to the top of the balloon (outside the photo frame?) but was wondering how that would affect the way the balloon breaks… If you still check this please let me know =)

  13. Leeuwtje says:

    Thanks!
    Just the info I was looking for. I guess above is also the case for studio flashes?

    Leeuwtje

    Photosbykev response: Studio flash units typically have much longer flash durations nearer to 1/1000 second

  14. photosbykev says:

    glad to be of help Kym, just shout if I can help you in any way

  15. Kimbo says:

    Morning Kev,

    I have spent eons trying to produce a single, decent ‘high speed’ shot. All of which, are c**p. Having just read your ditty above, the penny has finally dropped. Of course, it all makes perfect sense to me now. So, huge thanks. (Pity my 580EX didn’t come with a decent instruction manual in the first place and I didn’t come upon your website sooner!)

    Happy snappin’

    Tutty bye

    Kym

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