What I'm saying is: suppose, the camera is in Auto (P), and ISO is set to 200. The metering system sets 1/250 f/8. Now let's set ISO to 400. The metering system sets 1/500 f/8. Thus, in this scenario, changing ISO setting changes the exposure and thus the "#photons". Right?
March 29, 2023
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For a given shutter speed and aperture, changing ISO will not change exposure. Given a shutter speed and letting the camera pick the aperture, changing ISO will change the aperture, and therefore the number of photons hitting the sensor. Given an aperture and letting the camera pick the shutter speed, changing ISO will change the shutter speed, and therefore the number of photons hitting the sensor.
But that's a discussion about metering and meter-mediated automation. I think it's confusing to conflate it with a discussion about exposure.
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Jim, I was trying to stay away from using the E word, at least for a brief moment, since it seems to cause so much misunderstanding… & boil down to physical essence. Also, as I said in my reply to self above, the “assuming phrase” isn’t correct & I posted too quickly. That said, I realize what you say about the E word is correct.
Cheers!
Jerry -
I had to read your post twice… and I’m trying to seek common ground here by distilling to physical essence (& at least for a moment avoiding the E word).
But, yes, the #photons hitting the sensor changes in the scenario you outlined - agreed. I think a beginner can understand that easily & it’s also technically correct. Now… once that understanding is had & everyone agrees THEN perhaps discuss with beginners the historical terms that map on to that physical essence - it might be less confusing for them.
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I think one of Bob's maximæ, "ISO last", helps ;)
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I also think that the best way for a beginner to learn photography is to turn off as much automation as possible. That was true in the film era, and I think it's still true. It's harder to figure out what's going on when the camera is making changes you don't fully understand.
The most common last words on aircraft flight recorders found after crashes: "Why is it doing that?" Apocryphal, but you get the idea.
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Certainly true (though it seems to me a bit shoulder discussion).
Still, if we take the shutter, aperture, ISO combinations in IIiah’s example above, the statements about the #photons hitting the sensor are correct & remain so, whether those combinations were manually set, or set (partially) by the metering system. Agreed?
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Well yes, the exposure changes, but it is because your choice to alter the camera's operating parameters while in a particular mode also changes how the metering operates (and hence what exposure is automatically set to compensate). Changing the ISO setting in Manual mode will cause no change in exposure, so I can't see how the ISO value itself can be held responsible.
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I previously posted:
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Yes, in that case the ISO setting changes the exposure in the same way as reading an article about ETTR can change the exposure. In both cases the target exposure has changed, and the overall system (either mechanically or by human action) reacted, and attempted to meet the new target.
While you can make a case that both the ISO setting and the article indirectly caused the exposure to change, I would not say that the ISO setting and the article directly caused the exposure to change.
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no one is questioning the word exposure in the dictionary. using the word or words can have different meanings . and in photography the word exposure is made up of 3 settings not 2 , its common fact and 99.999999% of photographers know that . its only that .00000000001 % dont understand, which kind of makes you wonder doesnt it [🙄
llilah quote:
What I'm saying is: suppose, the camera is in Auto (P), and ISO is set to 200. The metering system sets 1/250 f/8. Now let's set ISO to 400. The metering system sets 1/500 f/8. Thus, in this scenario, changing ISO setting changes the exposure and thus the "#photons". Right? -
As ISO doesn't contribute directly to actually exposing the sensor in any way, It cannot be considered exposure at all. The oft quoted "Exposure Triangle" is fundamentally flawed and is the source of much misinformation and confusion. ISO could absolutely be considered a part of a Brightness Triangle, but an Exposure Triangle, no.[/quote]
Yes, in that scenario, in an auto or semi-auto mode, changing the ISO can change how the camera will automatically set the exposure, but ISO itself isn't any more a component of that exposure than my fingers are - which can also change the exposure
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Then you need to go and change the Wikipedia entry.
en.wikipedia.org/wiki/Exposure_(photography)
You also need to change countless photography textbooks.
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Exactly, but for some reason many misunderstand it and suggest that ISO somehow is a component of exposure. It isn't. In fact, ISO is defined through exposure.
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In this instance, I would respectfully disagree. The article was intend as a very brief and broad overview for a broad target audience and the focus was limited to the introduction of a few basic concepts. Within that scope, I find it not only reasonable but necessary to exclude material which would be entirely relevant and within the scope of a long-form presentation of greater depth intended for a different purpose and audience.
I encourage people to read widely from multiple sources and perspectives. Thanks for providing an environment where that's possible at a forum!
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Changing ISO setting may cause the change in exposure. That's not something new. "Directly" or "indirectly" are just words. The mechanism of such a change is better be explained in a transparent matter, or we will be stuck with "high ISO === high noise".
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Yes, in that scenario, in an auto or semi-auto mode, changing the ISO can change how the camera will automatically set the exposure, but ISO itself isn't any more a component of that exposure than my fingers are - which can also change the exposure
[/quote]fundamentally should a hamburger shop be called a beef burger shop ? the majority of people dont care what fundamentally anything means but they do know common terms to describe things to the* majority* of people/photographers.
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For all the techies. Define recording medium ? and lets be very specific which part of the sensor is the recording medium 🙄