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Multiple Flash alternate firing for high frame rates?

  
 
guyharrison
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p.1 #1 · p.1 #1 · Multiple Flash alternate firing for high frame rates?


I want to set up a flash system to match my 20 frame per second shooting speed.

I have Sony flashes and the Sony wireless controller. And Godox AD200 Pro Flashes and the Godox controller (for Sony)

My thought is to have the flashes fire alternately. It seems the max FPS for the flashes is just over 10 FPS. If I could get them to fire alternately instead of simultaneously then I should be able to get frame rate I am seeking.

Please note this is not about "multiflash" which usually means stroboscopic shooting. I need one flash, per frame, at 20 frames per second.

Can anyone give me some help on how to do this (or whether it can be done at all?).

I



Mar 22, 2022 at 02:21 PM
rico
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p.1 #2 · p.1 #2 · Multiple Flash alternate firing for high frame rates?


Two strobes or flashes can be alternatively triggered by using a Pocketwizard MultiMAX at the camera. You also need PW units for each light source. This might not be the kind investment in effort or money that appeals to you. Far easier is working within the parameters of your available flash. For example, Nikon's top flash is the SB-5000 and its capacitor is capable of repeated partial discharges at high frequency. The number of possible discharges at 20Hz is dependent on the energy setting:




Mar 22, 2022 at 03:02 PM
jeffbuzz
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p.1 #3 · p.1 #3 · Multiple Flash alternate firing for high frame rates?


As far as achieving your desired fps rate with fully synced lights (not alternating), that would depend largely on the capability of the camera and recycle rate of the strobe(s). I think all the Sony bodies have various caveats about diminishing frame rates when using flash and/or AF-C. You don't specify which camera. Although I assume a9 or a1 if expecting 20 fps.

If using a1, are you trying to use e-shutter too? That may create a new set of issues. Although a1 does flash sync the e-shutter, you would now need to consider the flash duration. The AD200 does show the duration so you can see how power output effects it.

My a9 II continuously triggers an AD200 via X2 trigger in mech shutter, 1/250th, Hi speed drive, AF-C, center tracking, flash mode M, 1/128 power. The AD200 shows a duration of 1/12190.

Whether you can achieve the power you need with the recycle time necessary to get close to the frame rate you want is totally a factor of power. More power = faster recycling. I'm getting ~f/2.8 @ ISO100 @ 2 meters.

These are the exif times I get from a short burst:

SubSecDateTimeOriginal : 2022:03:22 12:44:55.838-07:00
SubSecDateTimeOriginal : 2022:03:22 12:44:55.938-07:00
SubSecDateTimeOriginal : 2022:03:22 12:44:56.039-07:00
SubSecDateTimeOriginal : 2022:03:22 12:44:56.139-07:00
SubSecDateTimeOriginal : 2022:03:22 12:44:56.239-07:00
SubSecDateTimeOriginal : 2022:03:22 12:44:56.339-07:00
SubSecDateTimeOriginal : 2022:03:22 12:44:56.440-07:00
SubSecDateTimeOriginal : 2022:03:22 12:44:56.540-07:00
SubSecDateTimeOriginal : 2022:03:22 12:44:56.640-07:00
SubSecDateTimeOriginal : 2022:03:22 12:44:56.740-07:00
SubSecDateTimeOriginal : 2022:03:22 12:44:56.840-07:00
SubSecDateTimeOriginal : 2022:03:22 12:44:56.941-07:00

So I'm getting roughly 11fps at the above strobe settings. All images showed equal flash output.

I tried the same test using AF-S and also got ~11fps.






Edited on Mar 23, 2022 at 01:23 PM · View previous versions



Mar 22, 2022 at 03:26 PM
jeffbuzz
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p.1 #4 · p.1 #4 · Multiple Flash alternate firing for high frame rates?


HSS is a $h!t show in continuous Mid and Hi. Neither get above 7fps. Cont Lo works at 3 fps.

EXIF data shows flash firing is detected on every shot. But clearly many at Mid and Hi speed are either under power or not actually fired.

a9M2, AD200Pro, 1/500th mech shutter, HSS


















Mar 22, 2022 at 07:29 PM
guyharrison
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p.1 #5 · p.1 #5 · Multiple Flash alternate firing for high frame rates?


Thank you jeffbuzz! This gives me some real insight into what to expect.


Mar 24, 2022 at 08:11 AM







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