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Archive 2024 · A9 III + Godox Flash
  
 
jhapeman
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p.2 #1 · A9 III + Godox Flash


duncang wrote:
Budding A9 III users please go to the DxO site and request support for the A9 III. Currently scheduled for April.

https://www.dxo.com/supported-cameras/suggest-module/



They usually get there but they are kind of slow. Not sure asking will really help on a camera like this where it's 100% they will release it when they get around to it.


Feb 07, 2024 at 02:43 PM
docusync
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p.2 #2 · A9 III + Godox Flash


aCuria wrote:
I suppose this means the flash curve is always the same regardless of flash duration.

Correct

aCuria wrote:
Does this mean for a given shutter speed (say 1/8000s) we would want to choose a flash duration slightly longer than 1/8000s for maximum power?

Yes, that is absolutely correct, but I would also consider number of pops per cycle/recycling speed if shooting at high fps. A 1/256 you'd theoretically get twice more pops vs 1/128.

aCuria wrote:
And for the 1/8000s shutter, the flash power shooting at 1/1 and 1/7000s is effectively the same?

Pretty much, but the shutter delay can make a difference here though. I.e. it's easier to catch a long tail of a full power pop than a small abrupt 1/7000s pop. As long as we're catching the same fragment of light emission at 1/8000s - it should look the same.

duncang wrote:
Budding A9 III users please go to the DxO site and request support for the A9 III. Currently scheduled for April.
https://www.dxo.com/supported-cameras/suggest-module/


Just did - I saw this message after submission:
Good news, roadmap expects camera for 2024‑04.
Feb 07, 2024 at 05:03 PM
aCuria
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p.2 #3 · A9 III + Godox Flash


GMPhotography wrote:
See If I can put this in perspective to actually shooting . Let's say you have a group shot of 5 people in strong sunlight in the background and hitting them from behind so you need fill light. Today your shutter speed and sync speed is no greater than 1/250 of a second at lets say you want F8 to shoot at. Well F8 and 1/250 will not bring down the ambient light to match your flash output. Now lets say you can get F8 out of the flash but you cant't get the shutter speed faster with the global...Show more →

Don't get too excited, global shutter + flash as of 2/2024 represents "unrealized potential".

This is because the kinds of strobes we need to make full use of global shutter do not exist!

Lets have a simple example:

  1. suppose foreground exposure is good at 50ws (1/200s, iso 100)
  2. but background exposure needs to be cut by 3 stops
  3. Normally we use a 3 stop ND, but this means a big 400ws strobe is needed (50ws after punching through 3 stop ND)
  4. Or HSS is used but a big strobe is needed once again
  5. Now we can use an A9III, and push the shutter up by 4.25 stops (1/4000s) (3 stops to match the ND, +1.25 stop because base iso is 250) and theoretically use a 50ws strobe! this is what we want, get good results with just a speedlight.


However, this does not actually work because we need a strobe that emits 50ws at a T0.1 of 1/4000s

Now compare that to to the strobes we actually have:

  1. Broncolor 800L - 3ws at 1/4580s and 6ws at 1/3000s
  2. Profoto B1X - 16ws at 1/4780s or 32ws at 1/3800s
  3. Godox AD600 pro - 31.3ws at 1/4090s
  4. Godox AD400 pro - 25ws at 1/3930s
  5. Godox AD200 pro - 12.5ws at 1/5630s or 25ws at 1/3420s


Ultimately this means we will still have to carry around big strobes because the small ones do not emit enough light at high sync speeds.... Docusync was using the AD1200

What we need is for someone to make a speedlight capable of outputting 70ws, but this 70ws needs to come out at a T0.1 of at least 1/4000s but preferably even faster.


Edited on Feb 08, 2024 at 05:48 AM · View previous versions
Feb 07, 2024 at 10:34 PM
duncang
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p.2 #4 · A9 III + Godox Flash


aCuria wrote:
Don't get too excited, global shutter + flash as of 2/2024 represents "unrealized potential".

This is because the kinds of strobes we need to make full use of global shutter do not exist!

Lets have a simple example:

  1. suppose foreground exposure is good at 50ws (1/200s, iso 100)
  2. but background exposure needs to be cut by 3 stops
  3. Normally we use a 3 stop ND, but this means a big 400ws strobe is needed (50ws after punching through 3 stop ND)
  4. Or HSS is used but a big strobe is needed once again
  5. Now we can use an A9III, and push the shutter up


However, this does not actually work because we need a strobe that emits 50ws at a T0.1 of 1/4000s

Now compare that to to the strobes we actually have:

  1. Broncolor 800L - 3ws at 1/4580s and 6ws at 1/3000s
  2. Profoto B1X - 16ws at 1/4780s or 32ws at 1/3800s
  3. Godox AD600 pro - 31.3ws at 1/4090s
  4. Godox AD400 pro - 25ws at 1/3930s
  5. Godox AD200 pro - 12.5ws at 1/5630s or 25ws at 1/3420s


Ultimately this means we will still have to carry around big strobes because the small ones do not emit enough light at high sync speeds.... Docusync was using the AD1200

What we need is for someone to make a speedlight capable of outputting 70ws, but this 70ws needs to come out at a T0.1 of at least , 1/4000s preferably even faster.
...Show more →

I haven't looked at the math behind any of this but how is it do you think that at 1/16000s I can use the GN60 flash at 1/32 or perhaps it was 1/128 or even 1/256 (I can't recall exactly) to brightly light up a bird at 4 meters.

I was not expecting to get any light on the subject because at 1/16000s I figured the flash power would be so severely reduced it would be useless. That didn't seem to be the case.

Are you sure your assumptions work if you are able to adjust the timing so you get the peak output to coincide with the shutter. Isn't T0.1 power rating incorrect if the flash timing is delayed.
Feb 08, 2024 at 02:17 AM
aCuria
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p.2 #5 · A9 III + Godox Flash



duncang wrote:
I haven't looked at the math behind any of this but how is it do you think that at 1/16000s I can use the GN60 flash at 1/32 or perhaps it was 1/128 or even 1/256 (I can't recall exactly) to brightly light up a bird at 4 meters.

I was not expecting to get any light on the subject because at 1/16000s I figured the flash power would be so severely reduced it would be useless. That didn't seem to be the case.

Are you sure your assumptions work if you are able to adjust the timing so you get...Show more →

The flash delay can be calibrated in the A9iii, so I’m guessing it’s probably possible to nail the timing after some fiddling with it

The AD1200 pro emits 1200/256 = 4.7 WS with a T0.1 of 1/10860. If your shutter speed is faster than 1/10860 then you will get less than 4.7ws on your subject

Now the question you need to answer is whether 4.7ws is enough for what you want to do?

If a smaller strobe is used, afaik the power output in ws is lower at the same T0.1 value.




Feb 08, 2024 at 05:56 AM
rico
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p.2 #6 · A9 III + Godox Flash


docusync wrote:
Yes, it's crazy how simple the process has become now. All you need is to adjust the camera delay. Before you could do something similar with a PocketWizard that would adjust the flash delay but it 1) required an old school non IGBT flash with the longest duration possible, 2) you had to shoot this flash at full power and 3) nothing was guaranteed, and even 1/500s was considered as an achievement.

For strobe mavens like me, GS is revolutionary. All my frontline cameras are near 24MB (D3X, D500, A7ii, Z6) so this new sensor is a perfect fit. Being traditionally limited to X-sync 1/250s means far less control over ambient which, even at f/5.6, can creep into the exposure and throw a color cast. Ambient includes window light, artificial sources and even modelling lights. I have also mucked with programmed MultiMAX delays and that's a real trial-and-error PITA. With A9iii all that stuff is gone.


Feb 12, 2024 at 08:16 PM
InFocus2014
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p.2 #7 · A9 III + Godox Flash


aCuria wrote:
Don't get too excited, global shutter + flash as of 2/2024 represents "unrealized potential".

This is because the kinds of strobes we need to make full use of global shutter do not exist!

Lets have a simple example:

  1. suppose foreground exposure is good at 50ws (1/200s, iso 100)
  2. but background exposure needs to be cut by 3 stops
  3. Normally we use a 3 stop ND, but this means a big 400ws strobe is needed (50ws after punching through 3 stop ND)
  4. Or HSS is used but a big strobe is needed once again
  5. Now we can use an A9III, and push the shutter up


However, this does not actually work because we need a strobe that emits 50ws at a T0.1 of 1/4000s

Now compare that to to the strobes we actually have:

  1. Broncolor 800L - 3ws at 1/4580s and 6ws at 1/3000s
  2. Profoto B1X - 16ws at 1/4780s or 32ws at 1/3800s
  3. Godox AD600 pro - 31.3ws at 1/4090s
  4. Godox AD400 pro - 25ws at 1/3930s
  5. Godox AD200 pro - 12.5ws at 1/5630s or 25ws at 1/3420s


Ultimately this means we will still have to carry around big strobes because the small ones do not emit enough light at high sync speeds.... Docusync was using the AD1200

What we need is for someone to make a speedlight capable of outputting 70ws, but this 70ws needs to come out at a T0.1 of at least 1/4000s but preferably even faster.
...Show more →

Thank you for the reality check.



Feb 13, 2024 at 07:17 AM
GMPhotography
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p.2 #8 · A9 III + Godox Flash


My theory is if we can pull off at least 1/1200 shutter speed over the 1/250 sync we have today that's a few stops to the good. That may not be killing that much power on the strobe to pull that off. Big test needs to be done and see what we can do. No one will do it as they think 120 FPS is the cats meow. I get it but not what some of us need to hear.


Feb 13, 2024 at 07:25 AM
aCuria
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p.2 #9 · A9 III + Godox Flash



GMPhotography wrote:
My theory is if we can pull off at least 1/1200 shutter speed over the 1/250 sync we have today that's a few stops to the good. That may not be killing that much power on the strobe to pull that off. Big test needs to be done and see what we can do. No one will do it as they think 120 FPS is the cats meow. I get it but not what some of us need to hear.

Using a 1/1200 shutter on the A9iii (iso 250) is equivalent to using a 1 stop ND filter (and iso 100)

From your previous post what you want is to carry smaller strobes. You would need to find a 200ws strobe that has a T0.1 of 1/1200s at full power to achieve this






Feb 13, 2024 at 08:31 PM
rico
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p.2 #10 · A9 III + Godox Flash


One of my standard metrics is ISO 100, f/5.6, 1/250s, 1200J to fully illuminate my studio indirectly (wall bounce). To more completely suppress the overhead fluorescents and their color casting, I would prefer a shutter speed of 1/1000s at least. The Profoto Pro-11 pack can meet that requirement in Freeze Mode, specifically 1200J, 1/1500s (t0.1) which is pretty impressive. So is the price.


Feb 13, 2024 at 09:08 PM
GMPhotography
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p.2 #11 · A9 III + Godox Flash


Now this global shutter is out flash OEMS will hopefully will work on capability
Feb 13, 2024 at 09:25 PM
aCuria
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p.2 #12 · A9 III + Godox Flash


rico wrote:
One of my standard metrics is ISO 100, f/5.6, 1/250s, 1200J to fully illuminate my studio indirectly (wall bounce). To more completely suppress the overhead fluorescents and their color casting, I would prefer a shutter speed of 1/1000s at least. The Profoto Pro-11 pack can meet that requirement in Freeze Mode, specifically 1200J, 1/1500s (t0.1) which is pretty impressive. So is the price.

Why not turn the fluorescents off and eliminate the color cast completely...
Feb 13, 2024 at 09:47 PM
aCuria
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p.2 #13 · A9 III + Godox Flash


GMPhotography wrote:
Now this global shutter is out flash OEMS will hopefully will work on capability

I suppose one way this can be achieved is to take a large flash bulb, put it into a speedlight and under-power it.

For example, the AD600 pro at 1/8 power (75ws) has a T0.1 of 1/2460s

If we can put the AD600 pro bulb into the body of a V1 I suppose you can still drive it at 75ws to get the same T0.1 of 1/2460s

However, this contraption may only go down to 1/32 power though.
Feb 13, 2024 at 10:14 PM
hiepphotog
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p.2 #14 · A9 III + Godox Flash


aCuria wrote:
Don't get too excited, global shutter + flash as of 2/2024 represents "unrealized potential".

This is because the kinds of strobes we need to make full use of global shutter do not exist!

Lets have a simple example:

  1. suppose foreground exposure is good at 50ws (1/200s, iso 100)
  2. but background exposure needs to be cut by 3 stops
  3. Normally we use a 3 stop ND, but this means a big 400ws strobe is needed (50ws after punching through 3 stop ND)
  4. Or HSS is used but a big strobe is needed once again
  5. Now we can use an A9III, and push the shutter up


However, this does not actually work because we need a strobe that emits 50ws at a T0.1 of 1/4000s

Now compare that to to the strobes we actually have:

  1. Broncolor 800L - 3ws at 1/4580s and 6ws at 1/3000s
  2. Profoto B1X - 16ws at 1/4780s or 32ws at 1/3800s
  3. Godox AD600 pro - 31.3ws at 1/4090s
  4. Godox AD400 pro - 25ws at 1/3930s
  5. Godox AD200 pro - 12.5ws at 1/5630s or 25ws at 1/3420s


Ultimately this means we will still have to carry around big strobes because the small ones do not emit enough light at high sync speeds.... Docusync was using the AD1200

What we need is for someone to make a speedlight capable of outputting 70ws, but this 70ws needs to come out at a T0.1 of at least 1/4000s but preferably even faster.
...Show more →

Needing 50-70ws with a t0.1 faster than 1/4000s is, IMO, not very common. I am using an on-location lighting scenario.

Following the Sunny 16 rule, a shutter speed of 1/4000s is equivalent to shooting under bright daylight at f/4 ISO 250. Taking the Godox V1 with a Guide Number of 92' at the 50mm setting, the appropriate flash-to-subject distance at full power, ISO 250, and f/4 is 32'. For a landscape shot framing a full body of a 5'7" person using a 50mm lens, a camera-to-subject distance of about 11.6' is needed (assuming it is the same as the flash-to-subject distance). Halving the 32' flash distance (16') for a looser framing of a full body would reduce the required output to 1/4 full power. Although I do not have the flash duration for the Godox V1 at 1/4 power (25ws), the similar AD100 Pro was measured at 1/3020s t0.1 by Robert Hall, suggesting it is reasonably close to the 1/4000s SS. Adjusting the framing or using accessories like a Clic Magnum or fresnel to zoom in could further reduce the power and quicken the flash duration. Unless you intend to underexpose a sunny background by 1-2 stops (1/8000s-1/16000s at f/4) or throw light from further away on a sunny day, achieving this may be possible with just the AD100 Pro. Lower ambient light would provide even more flexibility.

Consequently, I find the GS feature on the A9III quite useful in most situations with standard equipment. However, in some extreme cases, regardless of High-Speed Sync or Global Shutter, a larger strobe becomes necessary.
Feb 16, 2024 at 01:30 AM
aCuria
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p.2 #15 · A9 III + Godox Flash


hiepphotog wrote:
Needing 50-70ws with a t0.1 faster than 1/4000s is, IMO, not very common. I am using an on-location lighting scenario.

Following the Sunny 16 rule, a shutter speed of 1/4000s is equivalent to shooting under bright daylight at f/4 ISO 250. Taking the Godox V1 with a Guide Number of 92' at the 50mm setting, the appropriate flash-to-subject distance at full power, ISO 250, and f/4 is 32'. For a landscape shot framing a full body of a 5'7" person using a 50mm lens, a camera-to-subject distance of about 11.6' is needed (assuming it is the same as the flash-to-subject distance)....Show more →

Do you have a link to robert hall's measurements?, I do use the AD100 and would be interested to see the measurements.

I did a spreadsheet, the equivalent settings are as follows:


  1. No ND, 1/200s, = A9iii, 1/500s
  2. 1 stop ND, 1/200s, = A9iii, 1/1000s
  3. 2 stop ND, 1/200s, = A9iii, 1/2000s
  4. 3 stop ND: 1/200s, = A9iii, 1/4000s


Note that 600ws with a 3 stop ND, and the AD600 strobe at 600ws, requires a strobe that can do 75ws faster than 1/4000s.

Its not uncommon to use a 3 stop ND. If I do use a ND, its usually a 3 stop... because I tend to use fixed NDs and they come in 3, 6 and 10 stop.

I think where you went wrong is

1) assuming we are not trying to under expose the background. This assumption is entirely incorrect.
2) assuming we are not using a softbox or umbrella when running those guide numbers
3) assuming we can zoom in with the strobe. What if its a group photo?

The holy grail here is to light a group shot in full sun with 2x AD100 strobes and 2 umbrealla softboxes.
Feb 16, 2024 at 12:15 PM
hiepphotog
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p.2 #16 · A9 III + Godox Flash


aCuria wrote:
Do you have a link to robert hall's measurements?, I do use the AD100 and would be interested to see the measurements.

I did a spreadsheet, the equivalent settings are as follows:


  1. No ND, 1/200s, = A9iii, 1/500s
  2. 1 stop ND, 1/200s, = A9iii, 1/1000s
  3. 2 stop ND, 1/200s, = A9iii, 1/2000s
  4. 3 stop ND: 1/200s, = A9iii, 1/4000s


Note that 600ws with a 3 stop ND, and the AD600 strobe at 600ws, requires a strobe that can do 75ws faster than 1/4000s.

Its not uncommon to use a 3 stop ND. If I do use a ND, its usually a 3 stop... because I tend to...Show more →

RH video:



Your previous post didn't delve into the aperture and flash distance aspects, prompting me to provide additional context. This was done to emphasize that the requirement of 50-75ws at 1/4000s is not a common occurrence. Considering a standard camera with a 3-stop ND filter example you mentioned, the need for a 600ws blast is not encountered frequently.

While the global shutter may not address every situation, it proves effective in many cases. It's also conceivable that people will devise workaround solutions to adapt global shutter technology for those instances where it might work initially.
Feb 17, 2024 at 08:48 AM
aCuria
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p.2 #17 · A9 III + Godox Flash


hiepphotog wrote:
RH video:



Your previous post didn't delve into the aperture and flash distance aspects, prompting me to provide additional context. This was done to emphasize that the requirement of 50-75ws at 1/4000s is not a common occurrence. Considering a standard camera with a 3-stop ND filter example you mentioned, the need for a 600ws blast is not encountered frequently.

While the global shutter may not address every situation, it proves effective in many cases. It's also conceivable that people will devise workaround solutions to adapt global shutter technology for those instances where it might work initially.

I suppose my example was contrived, I started with what I could do with the AD600 and 3 stop ND, and then worked backwards to figure out what was needed to replicate that with the A9iii.

However do note that It is not uncommon to need 600ws when using NDs.

Lets look at this example on strobist:

https://strobist.blogspot.com/2014/07/full-sun-group-shot.html

He is using an apsc leaf shutter camera at 1/1000th at f/8 at the base ISO of 200, with 2 strobes set at 2 x 320ws.

We can look at some equivalent settings:

  1. f/8, 1/1000s, 2 x 320ws, iso 200
  2. f/8, 1/500s, 2 x 320ws, iso 100
  3. f/8, 1/250s, 2 x 640ws, iso 100, 1 stop ND
  4. f/8, 1/125s, 2 x 1280ws, iso 100, 2 stop ND


You can see that 600ws is not that crazy after all.

Note that something like the A7Cii only syncs at 1/160s.
Feb 17, 2024 at 09:58 AM
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p.2 #18 · A9 III + Godox Flash


Thank you for this post!!!
I've been doing lots and lots of tests with the A9III and the Godox AD1200pro and AD600pro.

I always get a slower fps than you mentioned. When I set the trigger (pro II) to legacy mode, the flashes don't fire at all.

EDIT: I forgot to add, I did try with compatible Lenses and updated firmware.

Help pretty please . Thank you!
Apr 01, 2024 at 05:13 AM
hiepphotog
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p.2 #19 · A9 III + Godox Flash


Thanks to docusync initiating this discussion on the advantages of Global Shutter for strobe usage.

Yesterday, I came across a video on Rob Hall's channel that provided a thorough analysis of the relationship between high shutter speed and flash duration. In essence, although we may not fully utilize the flash power in every scenario, Global Shutter still presents superior efficiency and convenience compared to traditional methods.
May 02, 2024 at 10:34 PM
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p.2 #20 · A9 III + Godox Flash


wolfamri wrote:
Thank you for this post!!!
I've been doing lots and lots of tests with the A9III and the Godox AD1200pro and AD600pro.

I always get a slower fps than you mentioned. When I set the trigger (pro II) to legacy mode, the flashes don't fire at all.

EDIT: I forgot to add, I did try with compatible Lenses and updated firmware.

Help pretty please . Thank you!

My apologies - I haven't been visiting this thread for a while!
You probably figured it out already - you need to switch the Exposure/Color -> Flash -> Sync Terminal Settings to "Always" if you're using the ISO pin mode. The ISO pin disables all fancy MI communications and the camera "thinks" it got nothing to trigger if you leave it in "Auto".

Excerpt from the manual:
"Auto":
A flash signal is output from the (flash sync) terminal only when the flash is connected to the Multi Interface [MI] Shoe and ready to fire.
"Always:
Always outputs a flash signal when shooting.

MI communication is slow, and you'd get around 10fps at best. The MI mode won't work for any kind of action shots because it increases shutter lag quite significantly even if TTL is disabled. The dumb (ISO pin) mode doesn't introduce any noticeable delays and you'd be surprised how many pops you can squeeze from your flash if you stay around 1/64 - 1/128. Don't forget to adjust the sync delay to catch the peak of light emission if you're exposing at 1/500s or faster.
May 03, 2024 at 11:08 PM
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