Auto ISO with Flash problem

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Ad Astra

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I am having unexpected results when using Auto ISO with flash and wondered if anybody can help.

I am aiming to have manual exposure on the camera (a Nikon Z7II) with auto ISO and set shutter and aperture manually and let auto ISO float the ISO to get a good background exposure. This works as expected when the flash is turned off.

I am looking to set flash manually to 1/128th power, attach a better beamer and get a little fill light on the subject. Auto FP is turned on in camera to allow high speed flash sync when shutter speed greater than sync speed of 1/200. High Speed Sync icon is then turned on on the flash menu. Flash is a Godox V860III(N).

This is when things go wrong, turning the flash on appears to disable auto ISO, it still says auto ISO but ISO drops to 64 and the image is black due to under exposing.

Any suggestions please?
 
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Ad Astra said:
I am having unexpected results when using Auto ISO with flash and wondered if anybody can help.

I am aiming to have manual exposure on the camera (a Nikon Z7II) with auto ISO and set shutter and aperture manually and let auto ISO float the ISO to get a good background exposure. This works as expected when the flash is turned off.

I am looking to set flash manually to 1/128th power, attach a better beamer and get a little fill light on the subject. Auto FP is turned on in camera to allow high speed flash sync when shutter speed greater than sync speed of 1/200. High Speed Sync icon is then turned on on the flash menu. Flash is a Godox V860III(N).

This is when things go wrong, turning the flash on appears to disable auto ISO, it still says auto ISO but ISO drops to 64 and the image is black due to under exposing.

Any suggestions please?
Click to expand...
I have exactly the same issue on my D850 and D500. I have asked questions all over the place and I am yet to find an answer. Now when I use a flash I revert to manual everything and set my ISO, shutter speed, aperture and flash power manually. It is a pain for moving subjects and more often than not I miss the shot.

Good luck with finding a fix.
 
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Have you tried to disable auto-FP and keep your shutter speed below the 1/200? Use this a test to help discover the limitations of the system
 
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Ad Astra said:
I am having unexpected results when using Auto ISO with flash and wondered if anybody can help.

I am aiming to have manual exposure on the camera (a Nikon Z7II) with auto ISO and set shutter and aperture manually and let auto ISO float the ISO to get a good background exposure. This works as expected when the flash is turned off.

I am looking to set flash manually to 1/128th power, attach a better beamer and get a little fill light on the subject. Auto FP is turned on in camera to allow high speed flash sync when shutter speed greater than sync speed of 1/200. High Speed Sync icon is then turned on on the flash menu. Flash is a Godox V860III(N).

This is when things go wrong, turning the flash on appears to disable auto ISO, it still says auto ISO but ISO drops to 64 and the image is black due to under exposing.

Any suggestions please?
Click to expand...

I was having the same issue with my D500 and manual flash using auto ISO. The link will provide some good insight.

Camera Auto ISO and Nikon Flash

Camera Auto ISO with Nikon Flash
www.scantips.com
 
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Many thanks Mark, the article in your link explains lots of issues. The main one for me is that the camera set to auto ISO will not detect a remote flash. I will often set up two to three remote flashes (Nikon SB 5000) around a subjects frequent haunts. I guess Auto ISO and flash generally on Nikon cameras is something to avoid.
 
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If you want consistent results it is best to use the flash on a manual setting and adjust the output for the amount of light you want to add. with Auto ISO making exposure adjustments and flash fill adjustments on the fly it is too much for the camera to manage effectively.

In some situations the iTTL flash is terrific but in other situations I go full manual to insure consistent exposures.
 
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Talk about "A day late and a dollar short"! Just last week I was asked to make family group photo at my wife's 75th birthday celebration. My D500 was set for auto ISO / manual because I had been shooting birds the day before. I used TTL bounce flash for the portrait and chose the SS and aperture. Took 4 shots, took a quick look at the LCD and called it done. Next day when I downloaded to PSE I was stunned. I have never seen this kind of noise in any photo I have ever taken. I looked at the ISO. It was INSANE! I have never experienced or heard of this before. I didn't even know the camera could run ISO's that high. My wife is pretty disappointed and I feel pretty bad about it. It was a pretty tough way to learn a lesson.
 
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My limited experience with remote flashes (SB800s) and Auto ISO mirror much of what all of you report. Unreliable and/or confusing, so I no longer use that combo. While auto ISO has saved my bacon many, many times, it has cooked it too, sigh.
 
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Many thanks for all the replies. It looks like auto ISO and fill-in flash together is a no go.

It feels odd to me as if I select manual flash surely I am saying, its my responsibility and not for the camera to try and take over. I was hoping to use manual shutter and apperture with auto ISO to get a good background exposure and then just add a little bit extra light on the subject using manual flash with a low power setting.

I can use fully manual: shutter, apperture and ISO, but then I have to constantly adjust the ISO manually to get a good background exposure as the light changes or I move the camera position slightly.

How do others setup the flash when using a better beamer or equivalent flash extender?
 
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Ad Astra said:
Many thanks for all the replies. It looks like auto ISO and fill-in flash together is a no go.

It feels odd to me as if I select manual flash surely I am saying, its my responsibility and not for the camera to try and take over. I was hoping to use manual shutter and apperture with auto ISO to get a good background exposure and then just add a little bit extra light on the subject using manual flash with a low power setting.

I can use fully manual: shutter, apperture and ISO, but then I have to constantly adjust the ISO manually to get a good background exposure as the light changes or I move the camera position slightly.

How do others setup the flash when using a better beamer or equivalent flash extender?
Click to expand...

What you need to do when mixing ambient with flash is to establish the ambient exposure at the settings you want to use, then either if you have a flash meter, set the flash to 1/2/3 stops or whatever power you want under the ambient. Watch for your flash sync speed. If the shutter speed is over that use high speed sync but in that mode the flash power will be reduced. No problenm if the flash/flashes are close to the subject. No flash meter? Experiment - it just takes longer. If you have advance notice of where and what you are shooting a bit of practice before you do the shoot will make it easier. You might be able to get away with TTL on the flash set to minus EV power, or just remotely change the flash power as you go.
 
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I just wanted to add my experience from yesterday, as I had never come across it before.
I was doing photoshoot where I had fluctuating ambient light due to clouds passing in front of sun. My main exposure for the scene was from ambient light.
I was also using a flash to create a spot on the background of my scene to create separation for subject.
I was using Nikon Z6, and my flash was a Godox TT685 controlled by XT-1 trigger.
The ambient settings I was getting was around 1600 ISO, 1/400 sec, F2. I was in manual mode. But because ambient light was causing exposure to bounce up and down, I decided I would switch onto auto-ISO, to let the ISO move with changing light.
I took a test shot.... came out really dark. I couldn't work out what was going on, until I had a close look at top display panel, and saw auto-iso was off, and iso had defaulted back to manual ISO I had set... which was 160 ISO.
At the time, couldn't figure out what was going on, so reverted back riding my ISO up and down manually.
But then after googling, found this forum where others had experienced the same.
Learn something new every day. (y)
 
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Mark 10000 said:
I just wanted to add my experience from yesterday, as I had never come across it before.
I was doing photoshoot where I had fluctuating ambient light due to clouds passing in front of sun. My main exposure for the scene was from ambient light.
I was also using a flash to create a spot on the background of my scene to create separation for subject.
I was using Nikon Z6, and my flash was a Godox TT685 controlled by XT-1 trigger.
The ambient settings I was getting was around 1600 ISO, 1/400 sec, F2. I was in manual mode. But because ambient light was causing exposure to bounce up and down, I decided I would switch onto auto-ISO, to let the ISO move with changing light.
I took a test shot.... came out really dark. I couldn't work out what was going on, until I had a close look at top display panel, and saw auto-iso was off, and iso had defaulted back to manual ISO I had set... which was 160 ISO.
At the time, couldn't figure out what was going on, so reverted back riding my ISO up and down manually.
But then after googling, found this forum where others had experienced the same.
Learn something new every day. (y)
Click to expand...
Best way to control ambient exposure in these circumstances is by using shutter speed. At 1/400 you must have been using HSS?
 
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Mark 10000 said:
yes, in HSS... think I had set flash to be about 1/32 power... was just an accent light in background to lift exposure up a bit.
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HSS drastically reduces flash power anyway so you might not need to manually reduce it. However, aperture will affect the flash exposure just as shutter speed controls the ambient so opening the aperture will lighten anything the flash is illuminating without affecting the ambient. If you are wide open anyway rather than increasing the ISO, raising the flash power is better.
 
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dabhand16 said:
HSS drastically reduces flash power anyway so you might not need to manually reduce it. However, aperture will affect the flash exposure just as shutter speed controls the ambient so opening the aperture will lighten anything the flash is illuminating without affecting the ambient. If you are wide open anyway rather than increasing the ISO, raising the flash power is better.
Click to expand...
Im not sure you got the jist of my post... I understand everything your commenting on.... but my post was to concur with everyone else about how auto-iso disables when using OCF. And I was trying to use auto-iso because of fluctuating lighting conditions, rather than having to manually ride the settings up and down.
Im aware of power loss incurred by HSS. (y) (y)
 
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Mark 10000 said:
Im not sure you got the jist of my post... I understand everything your commenting on.... but my post was to concur with everyone else about how auto-iso disables when using OCF. And I was trying to use auto-iso because of fluctuating lighting conditions, rather than having to manually ride the settings up and down.
Im aware of power loss incurred by HSS. (y) (y)
Click to expand...

In changing ambient light and using a flash, the shutter speed is the tool to use though. ISO changes every part of the image, not just the ambient.
 
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dabhand16 said:
In changing ambient light and using a flash, the shutter speed is the tool to use though. ISO changes every part of the image, not just the ambient.
Click to expand...
oh apologies... i get what you mean now 🙏. yes agreed. I was just more comfortable in this instance for the subject matter, to keep shutter at 400... its where i wanted it. The iso wasnt going to jump around that much to change the effective flash exposure, and it was just a backlight so i wasnt too concerned about being slightly over or under exposed. And I dont like going too high with shutter in HSS, cause every stop higher dramatically lowers effective output of flash. Normally, I always stay in flash sync speed, even when shooting in sun. Use ND's... this time was an exception. It was a very unique setting.
 
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