Sony A7III w/Godox V860 II Flash - What is going on!?

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Benjy2014 Regular Member • Posts: 133
Sony A7III w/Godox V860 II Flash - What is going on!?

Hi everyone,

I haven't posted on here for a while - Forgive me!  Also apologies for the long post - This is an important one for me to try and seek help with.

If anyone's able to shed some light (forgive the pun!) on the below issues regarding my camera / flash setup, it would be hugely appreciated; I am literally going round in circles wondering what is going on!

Worth stating that my camera of choice at the minute is my Sony A7III and the flash I have mounted on top is the Godox V860 II (Sony).  It's worth also stating that I always shoot RAW and usually shoot between Manual Mode (with Auto-ISO on) and Aperture Priority (with Auto ISO Min SS on).

Two issues at hand then when using the flash:

1. ISO Issue: Issue with the camera choosing half Auto-ISO values as opposed to using more flash power. See below.

2. Max Shutter Speed Issue: When shooting quicker than 1/250, the camera defaults to 100 ISO, rendering shots far too dark. See below.

For the below tests, my flash is in TTL mode with HSS turned on.

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ISO Issue

Manual Mode

  • 1/250, F4, Auto ISO (100-3200) - Shoots at 1600 ISO
  • 1/250, F4, Auto ISO (100-6400) - Shoots at 3200 ISO
  • 1/250, F4, Auto ISO (100-12800) - Shoots at 6400 ISO

Narrowing the aperture (from F4 -> F13) to see what happens:

  • 1/250, F13, Auto ISO (100-3200) - Shoots at 1600 ISO
  • 1/250, F13, Auto ISO (100-6400) - Shoots at 3200 ISO
  • 1/250, F13, Auto ISO (100-12800) - Shoots at 6400 ISO

Why does the camera always choose to shoot as half the selected Auto ISO?

Slowing down the shutter speed (1/250 -> 1/60) to see if this helps with the Auto ISO selection:

  • 1/60, F4, Auto ISO (100-3200) - Shoots at 1600 ISO
  • 1/60, F4, Auto ISO (100-6400) - Shoots at 2500 ISO
  • 1/60, F4, Auto ISO (100-12800) - Shoots at 2500 ISO

This appears to find a balance at 2500 ISO, presumably with very minimal flash power.  Why does it do this, i.e. Use less flash power / higher ISO as opposed to high flash power / low ISO?

It's worth mentioning at this point then that when I shoot in Manual Mode with the flash attached, given the above issues, I usually result in setting the Auto ISO at either 100-800 or 100-1600, which results in shots at 400 ISO or 800 ISO, respectively (bumps the flash power up as opposed to the ISO, which is what I am after).  Although this meets my use-case, I wonder if I'm missing something here?

Aperture Priority Mode

  • F4, Auto ISO (100-3200), Auto ISO Min SS (1/250) - Shoots at 1600 ISO, 1/100
  • F4, Auto ISO (100-6400), Auto ISO Min SS (1/250) - Shoots at 3200 ISO, 1/160 or 1/200
  • F4, Auto ISO (100-12800), Auto ISO Min SS (1/250) - Shoots at 100 ISO, Correct shutter speed - 1/250 - Too dark
  • F4, Auto ISO (100-25600), Auto ISO Min SS (1/250) - Shoots at 100 ISO, Correct shutter speed - 1/250 - Too dark

What is going on here - The camera appears to have the same behaviour as above until it manages to shoot at my given minimum shutter speed (1/250), at which point, the camera defaults to ISO 100 - Rendering the image far too dark.

I can't seem to find a way around this, hence when I'm using flash, I tend to always shoot in Manual Mode with the above workaround mentioned above.

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Max Shutter Speed Issue

Manual Mode

  • 1/500, F4, Auto ISO (100-3200) - Shoots at 100 ISO
  • 1/500, F4, Auto ISO (100-6400) - Shoots at 100 ISO
  • 1/500, F4, Auto ISO (100-12800) - Shoots at 100 ISO
  • 1/500, F4, Auto ISO (100-25600) - Shoots at 100 ISO
  • 1/500, F4, Auto ISO (100-64000) - Shoots at 100 ISO
  • 1/500, F4, Auto ISO (100-128000) - Shoots at 100 ISO

Why does it do this with any shutter speed > 1/250 (i.e. 1/320, 1/400, 1/500)?  Am I missing some fundamental settings between the camera and/or flash?  I have HSS selected on the flash unit.

The only workaround I've managed to come up with to solve this is to set the ISO manually (trial and error).

Aperture Priority Mode

  • F4, Auto ISO (100-3200), Auto ISO Min SS (1/500) - Shoots at 1600 ISO, 1/100
  • F4, Auto ISO (100-6400), Auto ISO Min SS (1/500) - Shoots at 3200 ISO, 1/160 or 1/200
  • F4, Auto ISO (100-12800), Auto ISO Min SS (1/500) - Shoot at 100 ISO, Shutter speed 1/320 - Too dark
  • F4, Auto ISO (100-25600), Auto ISO Min SS (1/500) - Shoot at 100 ISO, Correct shutter speed - 1/500 - Too dark
  • F4, Auto ISO (100-64000), Auto ISO Min SS (1/500) - Shoot at 100 ISO, Correct shutter speed - 1/500 - Too dark
  • F4, Auto ISO (100-128000), Auto ISO Min SS (1/500) - Shoot at 100 ISO, Correct shutter speed - 1/500 - Too dark

What is going on here?

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Thank you in advance for this one

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