Questions about Auto ISO and Manual Exposure

[BLev65]

I'm a Nikon shooter... but this may apply to other systems as well..
I am reconsidering how I program my shooting banks/custom banks on my Nikon Z9 and Z8 cameras.
Quick backstory... historically (pre 7/2017) I shot in manual exposure only. During a marine mammals workshop I was persuaded by the tour leader to shoot in Aperture Priority with Easy Exposure compensation. The recommendations was based on the unique lighting associated with the transition from a dark coastline against water where humpback and orca would emerge. I've maintained the steadfast use of Aperture Priority w/ EZ exposure Compensation for everything but landscape photography ever since.
I am now considering a return to manual exposure for shooting in snow or prairie landscapes where birds take flight. I've found that my current method results in blown out highlights when birds exit the snow and fly across a darker background. I've known this problem for years and would fiddle with exposure compensation to compensate... At issue is the finger gymnastics that results in missed photos.
Having shot manual for years before, I know that if I set my exposure correctly for, let's say a swan on a snowy surface, and it suddenly flies across a field of trees, my base (ambient) exposure for the swans is accurate and the highlights will not be blown... this assumes that my ISO remains constant with respect to the swans on the snow and the swans flying across the stand of dark trees.
If you've made it this far and you understand me, then you may be able to help me with this question... If I am shooting in manual exposure and I've got swans on snow at: 1/1250 / f7.1 / ISO 800 and I have Auto ISO to vary, from 64 to 6400, won't the ISO change and over-expose my shot to maintain the exposure triangle I described for the birds on the snow. If that's the case, then shooting in manual with auto ISO is essentially the same as shooting in Aperture Priority with EZ exposure compensation and auto ISO... just without shutter speed limits. In other words, if I'm in manual w/ auto ISO, won't the ISO change and I will still blow-out the highlights?
My alternative is to set up two banks for manual exposure.. one at a lower ISO (800) for when there is plenty of ambient light and one for higher ISO (6400) for when I'm using an f6.3 lens or less available light.

I do a lot of cold/snow/overcast photography and I am looking for a better way to keep my subjects exposed correctly in snowy conditions.

bruce

 

[DRwyoming]

If I am shooting in manual exposure and I've got swans on snow at: 1/1250 / f7.1 / ISO 800 and I have Auto ISO to vary, from 64 to 6400, won't the ISO change and over-expose my shot to maintain the exposure triangle I described for the birds on the snow.

Yes

If that's the case, then shooting in manual with auto ISO is essentially the same as shooting in Aperture Priority with EZ exposure compensation and auto ISO... just without shutter speed limits. In other words, if I'm in manual w/ auto ISO, won't the ISO change and I will still blow-out the highlights?

Yes, however personally I much prefer Manual with Auto ISO as an automated exposure mode vs Aperture or Shutter Priority as I get to set what I consider the two most important creative controls (aperture and shutter speed) and within reason let the ISO float. In either Aperture or Shutter Priority the camera takes control of one of the creative controls that can't really be changed in post where within reason ISO can easily be changed in post. It's a lot easier to deal with a bit of noise than to deal with too slow of a shutter speed or too much/too little DoF.

But yes, in terms of your scenario of metering on snow and then a subject flying across a dark background full manual is the way to go if the light isn't changing rapidly.

The way I break it down is:

- If the backgrounds are changing rapidly or subject tones are changing rapidly but the light on the subjects is fairly constant I'll pre-meter, fix the ISO and shoot full Manual.

- If the light is changing rapidly (e.g. small to medium clouds rolling through and sometimes blocking the sun) but the subject tones and background tones aren't changing a lot I'll shoot an automated exposure mode and as posted above for me these days that's Manual with Auto ISO and use exposure comp as needed.

- If both light and subject/background tones are changing rapidly then flip a coin as any method will require frequent adjustments to expsosure or compensation controls. This is the tough situation as any way you slice it you'll have to keep making adjustments as things change.

 

[John Woodworth]

Yes to everything you said. Manual with Auto ISO is just another auto exposure mode with the issues you describe.

And my solution to the problem is the one you describe: Shooting Banks. I have a button programmed for quick transitions from Bank to Bank.

Another possibility is to shoot in manual and change (usually) shutter speed when the lighting changes. This can be sub-optimal, of course, since it might require raising ISO to accommodate an anticipated increase in shutter speed.

 

[bleirer]

Since those cameras are pretty much ISO invariant it's all good as long as you keep the whites from being blown in the worst case scenario. So you could set the shutter and aperture you want for the situation and either let the iso float but with enough EC to protect the brights in the worst case, maybe blinkies to check the worst case. Or full manual with iso set to the keep the brights from blowing in the worst case. Either way within a few stops since the iso is invarient it doesn't matter if you change brightness in post or via iso in the camera, as long as the brights are not blown.

 

[MrFotoFool]

Yes. I recently discovered how auto ISO works (use it with manual mode). I never used auto ISO on my DSLR (D850 and D500), but recently moved to Z8 and started using it. It works great most of the time for wildlife, but I found out over the last month that trying to use exposure compensation does not work (since I am in manual mode). On my DSLR's I used aperture priority with exposure compensation when needed.

The problem with the Z8 is that you have to go into the menu to turn auto ISO on or off (which is annoying - why can't they just put it in the ISO dial: spin down to the lowest ISO and then spin again and the next setting is auto). If someone knows of a custom function that will activate exposure compensation with manual and auto ISO, then please tell us. If not, I may go back to using aperture priority because I like having quick access to exposure compensation.

 

[cchuck]

Bruce and Dave,

Thanks for the clear explanations of the different scenarios. I benefitted from both question and answer. Thanks!

Chuck

 

[DRwyoming]

but I found out over the last month that trying to use exposure compensation does not work (since I am in manual mode).

Exposure compensation works fine when shooting Manual with Auto ISO with Nikon's Z cameras or DSLRs. As you dial in exposure compensation the ISO changes but the shutter speed and aperture stay at your settings. I use exposure comp all the time when shooting manual with Auto ISO.

The problem with the Z8 is that you have to go into the menu to turn auto ISO on or off

Actually it's quite easy to toggle Auto ISO on and off without going into the menus. You just press the ISO button up near the shutter release and spin the front sub-command dial to toggle between Auto and fixed ISO.

 

[BLev65]

Yes

Yes, however personally I much prefer Manual with Auto ISO as an automated exposure mode vs Aperture or Shutter Priority as I get to set what I consider the two most important creative controls (aperture and shutter speed) and within reason let the ISO float. In either Aperture or Shutter Priority the camera takes control of one of the creative controls that can't really be changed in post where within reason ISO can easily be changed in post. It's a lot easier to deal with a bit of noise than to deal with too slow of a shutter speed or too much/too little DoF.

But yes, in terms of your scenario of metering on snow and then a subject flying across a dark background full manual is the way to go if the light isn't changing rapidly.

The way I break it down is:

- If the backgrounds are changing rapidly or subject tones are changing rapidly but the light on the subjects is fairly constant I'll pre-meter, fix the ISO and shoot full Manual.

- If the light is changing rapidly (e.g. small to medium clouds rolling through) but the subject tones and background tones aren't changing a lot I'll shoot an automated exposure mode and as posted above for me these days that's Manual with Auto ISO and use exposure comp as needed.

- If both light and subject/background tones are changing rapidly then flip a coin as any method will require frequent adjustments to expsosure or compensation controls. This is the tough situation as any way you slice it you'll have to keep making adjustments as things change.

Thank you very much...
This helps me a lot, as I think about how to readjust my custom banks. I spent the last 6 years using aperture priority in wildlife photography and I'm done with it... The mode has served me well, but with Auto ISO available, I'll set two custom banks in manual exposure with different auto ISO limits and set two banks in manual with very different specific pre-set ISOs...

bruce

 

[BLev65]

Since those cameras are pretty much ISO invariant it's all good as long as you keep the whites from being blown in the worst case scenario. So you could set the shutter and aperture you want for the situation and either let the iso float but with enough EC to protect the brights in the worst case, maybe blinkies to check the worst case. Or full manual with iso set to the keep the brights from blowing in the worst case. Either way within a few stops since the iso is invarient it doesn't matter if you change brightness in post or via iso in the camera, as long as the brights are not blown.

This is not a good solution for birds that take flight and shift into different backgrounds quickly. As good as highlight conservation is, if you are at ISO 3200 and blow your highlights by a stop, you cannot recover the detail. On the other hand, if you are shooting in flat light and +2 stops is dialed in at a predefined ISO, shutter, and aperture the birds exposure will be the same even if it is now backed by a dark stand of trees.

 

[BLev65]

Yes. I recently discovered how auto ISO works (use it with manual mode). I never used auto ISO on my DSLR (D850 and D500), but recently moved to Z8 and started using it. It works great most of the time for wildlife, but I found out over the last month that trying to use exposure compensation does not work (since I am in manual mode). On my DSLR's I used aperture priority with exposure compensation when needed.

The problem with the Z8 is that you have to go into the menu to turn auto ISO on or off (which is annoying - why can't they just put it in the ISO dial: spin down to the lowest ISO and then spin again and the next setting is auto). If someone knows of a custom function that will activate exposure compensation with manual and auto ISO, then please tell us. If not, I may go back to using aperture priority because I like having quick access to exposure compensation.

This is an easy fix... set one custom function (C1) to manual with auto ISO and another (C2) to manual with fixed ISO. You can then program a button to quickly move between C1 and C2... I have pre-programmed my video button for this... this button, by the shutter release, has a divot, so you can feel it while you're shooting.

 

[BLev65]

Bruce and Dave,

Thanks for the clear explanations of the different scenarios. I benefitted from both question and answer. Thanks!

Chuck

You are welcome

 

[DRwyoming]

This is an easy fix... set one custom function (C1) to manual with auto ISO and another (C2) to manual with fixed ISO. You can then program a button to quickly move between C1 and C2... I have pre-programmed my video button for this... this button, by the shutter release, has a divot, so you can feel it while you're shooting.

You can do that, but Nikon has already made it very easy especially if you use the button hold for control buttons. Just press the existing ISO button up near the shutter release and then spin the front sub-command dial with a finger. That toggles back and forth between Auto ISO and fixed ISO.

 

[NorthernFocus]

In situations with rapidly varying BG brightness complete manual shooting(i.e. manual mode w/out auto ISO) is really the most controllable. It doesn't have to be complicated. Expose for the subject and leave it there. Unless the subject goes all the way from front lit to back lit(or vise versa) it works. Usually if it changes position that much there's time to adjust. Not always with BIF but life's not perfect.

 

[Abinoone]

Yes. I recently discovered how auto ISO works (use it with manual mode). I never used auto ISO on my DSLR (D850 and D500), but recently moved to Z8 and started using it. It works great most of the time for wildlife, but I found out over the last month that trying to use exposure compensation does not work (since I am in manual mode). On my DSLR's I used aperture priority with exposure compensation when needed.

The problem with the Z8 is that you have to go into the menu to turn auto ISO on or off (which is annoying - why can't they just put it in the ISO dial: spin down to the lowest ISO and then spin again and the next setting is auto). If someone knows of a custom function that will activate exposure compensation with manual and auto ISO, then please tell us. If not, I may go back to using aperture priority because I like having quick access to exposure compensation.

You might want to give the EV another try with auto ISO. I use it successfully all the time with my D850s when set to manual exposure and auto ISO.

 

[NorthernFocus]

Yes. I recently discovered how auto ISO works (use it with manual mode). I never used auto ISO on my DSLR (D850 and D500), but recently moved to Z8 and started using it. It works great most of the time for wildlife, but I found out over the last month that trying to use exposure compensation does not work (since I am in manual mode). On my DSLR's I used aperture priority with exposure compensation when needed.

The problem with the Z8 is that you have to go into the menu to turn auto ISO on or off (which is annoying - why can't they just put it in the ISO dial: spin down to the lowest ISO and then spin again and the next setting is auto). If someone knows of a custom function that will activate exposure compensation with manual and auto ISO, then please tell us. If not, I may go back to using aperture priority because I like having quick access to exposure compensation.

EC works in manual mode with auto ISO. If not then you must be hitting the max/min limits that are set in your camera.

You don't have to set auto iso in the menu. Hold the ISO button and turn front control wheel one click. Easy peasy. BTW same as D850.

 

[bleirer]

This is not a good solution for birds that take flight and shift into different backgrounds quickly. As good as highlight conservation is, if you are at ISO 3200 and blow your highlights by a stop, you cannot recover the detail. On the other hand, if you are shooting in flat light and +2 stops is dialed in at a predefined ISO, shutter, and aperture the birds exposure will be the same even if it is now backed by a dark stand of trees.

That's why I said adjust the EC for the worst case, to protect the highlights or in full manual set the iso for the worst case. The iso is invariant so it doesn't really make any difference within reason what the iso is, as long as the brights are not blown in camera. Exposure is shutter speed and aperture, which will be set manually, the brightening from iso can be done in camera or in post no difference, within a few stops.

 

[MrFotoFool]

Well I swear when I dial in exposure compensation it doesn't work, so I must be missing something. Not only does the exposure not appear to change, but the exposure dial in the viewfinder stays in the middle (instead of dropping two bars down if I am at minus two thirds like it does in aperture priority). I will have to play with it some more and I do appreciate the feedback.

As for changing out of auto ISO, a huge thank you to @DRwyoming and @NorthernFocus for telling me that I need to use the front dial. Since the ISO (not in auto) is normally changed with the rear dial, it never occured to me to try the front. You two have helped me more than you know.

 

[BillW]

Well I swear when I dial in exposure compensation it doesn't work, so I must be missing something. Not only does the exposure not appear to change, but the exposure dial in the viewfinder stays in the middle (instead of dropping two bars down if I am at minus two thirds like it does in aperture priority). I will have to play with it some more and I do appreciate the feedback.

As for changing out of auto ISO, a huge thank you to @DRwyoming and @NorthernFocus for telling me that I need to use the front dial. Since the ISO (not in auto) is normally changed with the rear dial, it never occured to me to try the front. You two have helped me more than you know.

Do you have you Z8 EVF set to show the effects of your various settings? I think it is custom menu D8.

 

[DRwyoming]

Not only does the exposure not appear to change, but the exposure dial in the viewfinder stays in the middle (instead of dropping two bars down if I am at minus two thirds like it does in aperture priority).

What you're describing is normal and something that tangles folks up fairly often. Nikon could have implemented the display better when shooting Manual with Auto ISO but basically it breaks down like this:

- In traditional auto exposure modes like Shutter or Aperture Priority or Program mode you see an exposure compensation adjustment scale in the viewfinder when you're making adjustments as well as an amber numerical representation like -0.7 so you can dial exposure comp up or down as desired. But when you've finished making the adjustment and have anything other then zero dialed in what you see in the Z8 is the adjustment scale that still shows you how much compensation is dialed in. If you reset the exposure comp adjustment to zero the scale disappears once you stop adjusting the compensation.

- When shooting full manual with manual ISO the camera displays an exposure meter(basically a light meter taking into account the camera settings) while shooting. That exposure meter is using the same viewfinder graphics icon used as the exposure comp adjustment scale and that's a big part of the confusion when shooting manual with Auto ISO.

- When shooting manual with Auto ISO in a Nikon the camera shows an exposure comp adjustment scale while you're making the exposure comp adjustment as well as the numeric representation. But when you finish the adjustment and continue shooting the camera reverts to showing an exposure meter just like it did in full manual with manual ISO and a small +/- icon that tells you some exposure comp has been dialed in but not how much. But since you're in an automatic exposure mode (Auto ISO) the meter will always stay centered until you hit a programmed high or low ISO limit. Basically that's the job of an auto exposure mode, keep the meter centered. As you dial in positive and negative exposure compensation you should always see a centered (zeroed) light meter unless the ISO is beyond the set limits and then it shows how much over or under exposed the image will be.

It can definitely be misleading since Nikon chose to use that scale as an exposure meter when shooting any variation of manual mode and to use the same graphic element as an exposure comp scale when shooting aperture priority, shutter priority or program mode when any non-zero exposure comp is dialed in.

Seems like a firmware change would be needed to make this behave differently and more like the traditional auto exposure modes but exposure comp definitely works in manual with Auto ISO even though the viewfinder display can be confusing.

This is real easy to test. Just take your camera with any lens and point it at a scene in steady light. This could be indoors or out and I just did this with my Z8 to double check. While shooting in Manual with Auto ISO set your aperture and shutter speed so the ISO is somewhere in the working range (not up against a menu set ISO limit) and notice what the ISO is. Now hit the exposure comp button and dial in say +1 stop of exposure compensation and then notice that the ISO has doubled from the previous setting. Similarly dial in -1 stop of exposure comp and notice that the ISO has dropped in half of the base setting.

Similarly you could start changing the settings like start cranking up the shutter speed and notice the ISO climbing. If you keep increasing the shutter speed you'll hit the top ISO of the camera or the high limit set in the menu and if you keep increasing the shutter speed then you'll see the light meter start dropping below zero telling you the camera is maxed out on ISO and now the image is under exposed because it can't push the ISO any higher. Basically that's what shows you in Manual with Auto ISO that graphical icon is an exposure meter and not an exposure comp adjustment scale which of course is very different than what you'd see when shooting aperture or shutter priority modes.

 

[MrFotoFool]

Thank you @DRwyoming !

 

[Patrick M]

Yes. I recently discovered how auto ISO works (use it with manual mode). I never used auto ISO on my DSLR (D850 and D500), but recently moved to Z8 and started using it. It works great most of the time for wildlife, but I found out over the last month that trying to use exposure compensation does not work (since I am in manual mode). On my DSLR's I used aperture priority with exposure compensation when needed.

The problem with the Z8 is that you have to go into the menu to turn auto ISO on or off (which is annoying - why can't they just put it in the ISO dial: spin down to the lowest ISO and then spin again and the next setting is auto). If someone knows of a custom function that will activate exposure compensation with manual and auto ISO, then please tell us. If not, I may go back to using aperture priority because I like having quick access to exposure compensation.

Z8 : auto ISO can be turned on or off by rotating the front dial while pressing the ISO button.

 

[MartyD]

Does Nikon's Highlight Weighted Metering mode provide any advantages when used in these situations?

 

[DRwyoming]

Does Nikon's Highlight Weighted Metering mode provide any advantages when used in these situations?

Sure, especially when shooting subjects that are prone to blowing out highlights like near frame filling shots of Bald Eagles or Osprey. Highlight weighted metering can give a bit of extra exposure protection by basically biasing the exposure to take into account highlights in the frame. That metering approach can apply to any exposure mode including Manual with Auto ISO.

In the scenario the OP described with birds metered against the snow and then flying across dark backgrounds I wouldn't expect Highlight Weighted Metering to save the day as that's a pretty big exposure swing depending on how much the subjects fill the frame but it might help a bit. I'd still go with full manual and manual ISO with exposure pre-set before the shooting begins for that kind of situation.

Personally I don't use Highlight Weighted Metering much in my shooting. I've played with it but I'm more familiar with how straight matrix metering works and how it reads a scene so I either use that or when shooting full manual with manual ISO I'll sometimes switch to spot metering to pre-set the exposure but after that metering doesn't really come into play during the actual shooting until I need to meter again for changing light.

 

[Gary Shackelford]

Yes

Yes, however personally I much prefer Manual with Auto ISO as an automated exposure mode vs Aperture or Shutter Priority as I get to set what I consider the two most important creative controls (aperture and shutter speed) and within reason let the ISO float. In either Aperture or Shutter Priority the camera takes control of one of the creative controls that can't really be changed in post where within reason ISO can easily be changed in post. It's a lot easier to deal with a bit of noise than to deal with too slow of a shutter speed or too much/too little DoF.

But yes, in terms of your scenario of metering on snow and then a subject flying across a dark background full manual is the way to go if the light isn't changing rapidly.

The way I break it down is:

- If the backgrounds are changing rapidly or subject tones are changing rapidly but the light on the subjects is fairly constant I'll pre-meter, fix the ISO and shoot full Manual.

- If the light is changing rapidly (e.g. small to medium clouds rolling through and sometimes blocking the sun) but the subject tones and background tones aren't changing a lot I'll shoot an automated exposure mode and as posted above for me these days that's Manual with Auto ISO and use exposure comp as needed.

- If both light and subject/background tones are changing rapidly then flip a coin as any method will require frequent adjustments to expsosure or compensation controls. This is the tough situation as any way you slice it you'll have to keep making adjustments as things change.

Dave, this is probably the most lucid description I have ever read that summarizes the strategy of shooting with auto ISO, especially in manual mode. Kudos to you!

 

[Dmacfarl]

You can do that, but Nikon has already made it very easy especially if you use the button hold for control buttons. Just press the existing ISO button up near the shutter release and then spin the front sub-command dial with a finger. That toggles back and forth between Auto ISO and fixed ISO.

Exactly. Works very well.