Auto ISO Concept Clarification

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In my Z7, I keep Auto ISO "on" all the time -- well, most of the time.
This is my understanding of Auto ISO and I would like to know if you guys agree with me.....

I set my ISO to be 200, say. That's my ISO. Now I shoot with A mode, at f/11. The camera will automatically give me 1/60 sec, say. Now, getting darker in the evening, my f/11 needs 1/8 sec. The camera only lowers the shutter to 1/30 sec, because that's my minimum shutter I had set. Then and only then, my Auto ISO kicks in and raises the ISO to 800 as the last resort. This is my understanding of Auto ISO behavior.

I tried Sony A7 III and Canon EOS RP. They do not allow me to set ISO value if Auto ISO is selected. That is, it is either-or. In other words, setting an ISO value and setting AUTO are mutually exclusive.... Their concept of Auto ISO seems to be a bit modified....





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I set my ISO to be 200, say. That's my ISO. Now I shoot with A mode, at f/11. The camera will automatically give me 1/60 sec, say. Now, getting darker in the evening, my f/11 needs 1/8 sec. The camera only lowers the shutter to 1/30 sec, because that's my minimum shutter I had set. Then and only then, my Auto ISO kicks in and raises the ISO to 800 as the last resort. This is my understanding of Auto ISO behavior.
I don't have a Z7 but that's how Auto ISO has worked on the three Nikon DSLR's I have owned. One clarification is that if your ISO automatically rises to the limit you have configured and the sensor still needs more light, the camera will then and only then use a lower shutter speed than you have configured. (It will never automatically change the aperture when you are using Aperture Priority.)
 
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I only use auto iso in manual mode so the camera can only change 1 variable
As Randy writes, you control ss and aperture, the camera then only chooses ISO.
The other way to look at this is that the camera automatically changes only the ISO except in the most extreme circumstances when the configured limits would cause an improper exposure. When using Auto ISO along with Aperture or Shutter Priority modes, the user has to set only one exposure control (aperture or shutter, respectively), whereas in Manual mode the user has to set two controls (both aperture and shutter).

I've come to believe over time that the choice of whether to use Auto ISO in Manual mode has partly to do with the kind of photography one typically does and mostly to do with what the user has become accustomed to using. The desired results can easily be achieved using Auto ISO whether it is along with the Manual, Aperture Priority or Shutter Priority mode.
 
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Butlerkid

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I have (rarely, thank goodness!) had situations where using AUTO ISO in manual mode, that the image exposure was extremely over or under exposed. The aperture and shutter speeds were not adjusted to correct for my error in aperture and/or shutter speed.
 
I have (rarely, thank goodness!) had situations where using AUTO ISO in manual mode, that the image exposure was extremely over or under exposed.
That's because of your skill that it has been rare. Extreme under or overexposure, when it does happen, is not because of any particular disadvantage of using Auto ISO with Manual mode, or when using it with Aperture or Shutter mode for that matter.
 

Butlerkid

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The other way to look at this is that the camera automatically changes only the ISO except in the most extreme circumstances when the configured limits would cause an improper exposure. When using Auto ISO along with Aperture or Shutter Priority modes, the user has to set only one exposure control (aperture or shutter, respectively), whereas in Manual mode the user has to set two controls (both aperture and shutter).

........


My only point was that when using Auto ISO in manual mode, the camera will not then adjust either aperture or exposure to achieve an acceptable exposure. Even in Aperture or shutter mode, if the camera bumps up against shutter limits, it can only adjust ISO. I must have mistaken your earlier statements that the camera would somehow adjust exposure. Sorry.
 
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I have used auto-iso in aperture priority mode for several years. I have also tried it in manual mode. My conclusion is that if you are shooting moving subjects, especially fast moving subjects, auto-iso in manual mode works well. But since I mostly photograph stationary subjects I prefer to stay in aperture priority with auto-iso turned on. I'm perfectly happy to let the camera choose the shutter speed as long as it is above my minimum, and that is just one less thing for me to worry about.
 

Butlerkid

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I have used auto-iso in aperture priority mode for several years. I have also tried it in manual mode. My conclusion is that if you are shooting moving subjects, especially fast moving subjects, auto-iso in manual mode works well. But since I mostly photograph stationary subjects I prefer to stay in aperture priority with auto-iso turned on. I'm perfectly happy to let the camera choose the shutter speed as long as it is above my minimum, and that is just one less thing for me to worry about.
I agree. For landscapes and architecture, I shoot aperture priority and ISO 64 and ignore shutter speed......UNLESS something is moving. LOL! Then I go manual, but still set the ISO, checking the histogram to ensure a proper exposure.
 
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I agree. For landscapes and architecture, I shoot aperture priority and ISO 64 and ignore shutter speed......UNLESS something is moving. LOL! Then I go manual, but still set the ISO, checking the histogram to ensure a proper exposure.
I do just that too, but the weakness in my system is forgetting to switch out of auto ISO when I shoot landscapes and similarly subjects. :(
 
Even in Aperture or shutter mode, if the camera bumps up against shutter limits, it can only adjust ISO.
That's true if the camera bumps up against the high shutter limit. If it bumps up against the minimum shutter setting and the maximum ISO setting in Aperture mode, it will lower the shutter speed to beneath its minimum setting.

I didn't realize that when shooting in Shutter mode, the camera won't change the aperture under any circumstance. However, I verified that you're correct about that.
 
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I use ONLY Manual at all times and for all purposes —often (but not always) in conjunction with Auto ISO and the ±EV Over-ride.

I absolutely never use either Aperture or Shutter Priority for any reason at all: neither of those options makes any sense to me at all!
 
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I wonder if I'm getting confused. Actually, I shouldn't wonder and should instead just accept that I'm confused. :eek:

For landscapes and architecture, I shoot aperture priority and ISO 64 and ignore shutter speed
I do just that too
If you're shooting handheld and not using Auto ISO, how do you know the shutter speed is fast enough? If a strong wind is blowing vegetation, how do you know the shutter speed is fast enough to stop the action?

That explains why I always shoot Auto ISO and Aperture priority when shooting handheld landscapes. When I've set the minimum shutter speed to the proper setting, only then can I ignore the shutter speed.

but the weakness in my system is forgetting to switch out of auto ISO when I shoot landscapes and similarly subjects. :(
When using a tripod, I always disable Auto ISO...except when I, like you, forget. I also always use a remote shutter...and when the mirror doesn't raise, that reminds me that I've also forgotten to turn the dial to that setting.

Another way of putting is that our system is just fine. The problem is when our system isn't used correctly due to operator error. :D
 
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