ISO RANGE

[JohnSil]

Extended vs. native/base ISO-range has no real meaning. It is only a decision of the manufacturer which ISO-values they call extended and which are called normal/base/native/whatever.

A wild guess how they differentiate: Define some noise-level as acceptable, and call every setting that produces more noise 'extended'.

Jib, actually, as it was explained somewhere, there is a rhyme and reason to ISO.

Native ISO is the camera producing images using it's actual signal to noise ratios natively. The extended ISO's are not being created directly by the camera's shooting procedure but being completely generated by the algorithms in the computer if the camera could actually generate them as part of the shooting process.

I'm sure those much more technical than myself will correct me and lay out the process in much clearer detail. BUT it's not arbitrary!

John

 

[Ed B]

Extended ISO to me has been the range not normally set or used and sometimes called boosted where you have to choose it to use it.

Some cameras do not let you use the extended range in auto ISO

I've never seen or heard of a camera that would let you manually do anything when set to auto ISO.

You've never seen or heard of a camera that allows you to manually limit the Auto ISO range?

The camera chooses the ISO setting.

The camera chooses within limits that can be imposed by the camera designers or the user.

With my main camera, I use auto ISO almost all the time with it set to 102,400 mostly (I would prefer to set a maximum of about 80,000 but it only uses intermediates when set to the next level).

Even if you could manually select the ISO, using auto ISO,

smith-jones can manually select the range in which Auto ISO operates (within some limits).

why would you choose 102,400?

To help ensure a result that's of satisfactory brightness when the situation requires it.

That sounds ridiculous.

What sounds ridiculous to one person can be very useful to others. That happens a lot.

Setting the auto ISO limit is entirely different than manually adjusting the ISO.

Of course it's different. You did not say manually adjusting the ISO, and neither did anyone else. That would be an oxymoron when discussing Auto ISO. What you said is this:

"I've never seen or heard of a camera that would let you manually do anything when set to auto ISO."

"I use auto ISO almost all the time with it set to 102,400" Yes, that's ridiculous!

You missed the actual context of the full statement, which is that the upper limit is manually set to 102,400. Not ridiculous at all if a person's priority is to get satisfactory brightness when the situation requires it.

Obviously, I misunderstood the comment, but he never said he sets the upper limit to 102,400.

Reread his original comment and you might understand.


As I said in my original comment, you can't make any ISO adjustments when the camera is set to auto ISO.

Yes, you can set a maximum limit, but that's a setting, not an adjustment.

 

[Fogel70]

Extended ISO to me has been the range not normally set or used and sometimes called boosted where you have to choose it to use it.

Some cameras do not let you use the extended range in auto ISO

I've never seen or heard of a camera that would let you manually do anything when set to auto ISO.

You've never seen or heard of a camera that allows you to manually limit the Auto ISO range?

The camera chooses the ISO setting.

The camera chooses within limits that can be imposed by the camera designers or the user.

With my main camera, I use auto ISO almost all the time with it set to 102,400 mostly (I would prefer to set a maximum of about 80,000 but it only uses intermediates when set to the next level).

Even if you could manually select the ISO, using auto ISO,

smith-jones can manually select the range in which Auto ISO operates (within some limits).

why would you choose 102,400?

To help ensure a result that's of satisfactory brightness when the situation requires it.

That sounds ridiculous.

What sounds ridiculous to one person can be very useful to others. That happens a lot.

Setting the auto ISO limit is entirely different than manually adjusting the ISO.

Of course it's different. You did not say manually adjusting the ISO, and neither did anyone else. That would be an oxymoron when discussing Auto ISO. What you said is this:

"I've never seen or heard of a camera that would let you manually do anything when set to auto ISO."

"I use auto ISO almost all the time with it set to 102,400" Yes, that's ridiculous!

You missed the actual context of the full statement, which is that the upper limit is manually set to 102,400. Not ridiculous at all if a person's priority is to get satisfactory brightness when the situation requires it.

Obviously, I misunderstood the comment, but he never said he sets the upper limit to 102,400.

Reread his original comment and you might understand.

As I said in my original comment, you can't make any ISO adjustments when the camera is set to auto ISO.

Yes, you can set a maximum limit, but that's a setting, not an adjustment.

You can adjust ISO indirectly when using auto-ISO by adjusting one or several of - aperture, shutter speed or exposure compensation. Depending on what mode you are using.

Just like you may adjust shutter speed indirectly by adjusting ISO.

 

[Ed B]

Extended ISO to me has been the range not normally set or used and sometimes called boosted where you have to choose it to use it.

Some cameras do not let you use the extended range in auto ISO

I've never seen or heard of a camera that would let you manually do anything when set to auto ISO.

You've never seen or heard of a camera that allows you to manually limit the Auto ISO range?

The camera chooses the ISO setting.

The camera chooses within limits that can be imposed by the camera designers or the user.

With my main camera, I use auto ISO almost all the time with it set to 102,400 mostly (I would prefer to set a maximum of about 80,000 but it only uses intermediates when set to the next level).

Even if you could manually select the ISO, using auto ISO,

smith-jones can manually select the range in which Auto ISO operates (within some limits).

why would you choose 102,400?

To help ensure a result that's of satisfactory brightness when the situation requires it.

That sounds ridiculous.

What sounds ridiculous to one person can be very useful to others. That happens a lot.

Setting the auto ISO limit is entirely different than manually adjusting the ISO.

Of course it's different. You did not say manually adjusting the ISO, and neither did anyone else. That would be an oxymoron when discussing Auto ISO. What you said is this:

"I've never seen or heard of a camera that would let you manually do anything when set to auto ISO."

"I use auto ISO almost all the time with it set to 102,400" Yes, that's ridiculous!

You missed the actual context of the full statement, which is that the upper limit is manually set to 102,400. Not ridiculous at all if a person's priority is to get satisfactory brightness when the situation requires it.

Obviously, I misunderstood the comment, but he never said he sets the upper limit to 102,400.

Reread his original comment and you might understand.

As I said in my original comment, you can't make any ISO adjustments when the camera is set to auto ISO.

Yes, you can set a maximum limit, but that's a setting, not an adjustment.

You can adjust ISO indirectly when using auto-ISO by adjusting one or several of - aperture, shutter speed or exposure compensation. Depending on what mode you are using.

Just like you may adjust shutter speed indirectly by adjusting ISO.

And, some people are capable of spinning just about anything.

 

[smith-jones]

Extended ISO to me has been the range not normally set or used and sometimes called boosted where you have to choose it to use it.

Some cameras do not let you use the extended range in auto ISO

I've never seen or heard of a camera that would let you manually do anything when set to auto ISO.

You've never seen or heard of a camera that allows you to manually limit the Auto ISO range?

The camera chooses the ISO setting.

The camera chooses within limits that can be imposed by the camera designers or the user.

With my main camera, I use auto ISO almost all the time with it set to 102,400 mostly (I would prefer to set a maximum of about 80,000 but it only uses intermediates when set to the next level).

Even if you could manually select the ISO, using auto ISO,

smith-jones can manually select the range in which Auto ISO operates (within some limits).

why would you choose 102,400?

To help ensure a result that's of satisfactory brightness when the situation requires it.

That sounds ridiculous.

What sounds ridiculous to one person can be very useful to others. That happens a lot.

Setting the auto ISO limit is entirely different than manually adjusting the ISO.

"I use auto ISO almost all the time with it set to 102,400" Yes, that's ridiculous!

Just because YOU can not shoot at night does not mean others do not want to.

WHY is it ridiculous to set 102400 as the max and not ISO 6400? (some people NEVER shoot at ISO 6400 so for THEM even that as maximum would be crazy).

If I set 51600 ISO as my maximum but that is not quite enough what would YOU do? (put the camera away I am guessing).

I have had normal (as in not Elvis with a Yeti) photos published in newspapers at ISOs over 51600.

Again with other cameras I do not even go off base (I used to have a Canon G10 and it was a lovely camera but even at ISO 400, I would get greater DR with my A7s at 25600 and would be happier above that too.

It is just the MAXIMUM I am prepared to muse and does not mean every (or ANY) photos will be at 102400. I would prefer it used ISO 100 for every shot but once in a while I will need much higher....there are two higher settings that I do almost never use but even they are there for a reason.

 

[Marek M]

Is extended iso range the only camera spec more useless than native iso range? I doubt any photographer is going to think an iso of 100k on aps sensor has an acceptable amount of noise.

But it may be a selling point.

Same with cars, top speed of over 200km/h, when you cannot drive like that anywhere in North America (except for Montana).

 

[smith-jones]

Extended ISO to me has been the range not normally set or used and sometimes called boosted where you have to choose it to use it.

Some cameras do not let you use the extended range in auto ISO

I've never seen or heard of a camera that would let you manually do anything when set to auto ISO.

You've never seen or heard of a camera that allows you to manually limit the Auto ISO range?

The camera chooses the ISO setting.

The camera chooses within limits that can be imposed by the camera designers or the user.

With my main camera, I use auto ISO almost all the time with it set to 102,400 mostly (I would prefer to set a maximum of about 80,000 but it only uses intermediates when set to the next level).

Even if you could manually select the ISO, using auto ISO,

smith-jones can manually select the range in which Auto ISO operates (within some limits).

why would you choose 102,400?

To help ensure a result that's of satisfactory brightness when the situation requires it.

That sounds ridiculous.

What sounds ridiculous to one person can be very useful to others. That happens a lot.

Setting the auto ISO limit is entirely different than manually adjusting the ISO.

Of course it's different. You did not say manually adjusting the ISO, and neither did anyone else. That would be an oxymoron when discussing Auto ISO. What you said is this:

"I've never seen or heard of a camera that would let you manually do anything when set to auto ISO."

"I use auto ISO almost all the time with it set to 102,400" Yes, that's ridiculous!

You missed the actual context of the full statement, which is that the upper limit is manually set to 102,400. Not ridiculous at all if a person's priority is to get satisfactory brightness when the situation requires it.

Obviously, I misunderstood the comment, but he never said he sets the upper limit to 102,400.

Reread his original comment and you might understand.

As I said in my original comment, you can't make any ISO adjustments when the camera is set to auto ISO.

Yes, you can set a maximum limit, but that's a setting, not an adjustment.

I said I set auto ISO to 102400 and I also said I would prefer to set the MAXIMUM to 80,000.

If you can not understand that it is not my problem.

You are right that some people will try and spin anything!

 

[Fogel70]

Extended ISO to me has been the range not normally set or used and sometimes called boosted where you have to choose it to use it.

Some cameras do not let you use the extended range in auto ISO

I've never seen or heard of a camera that would let you manually do anything when set to auto ISO.

You've never seen or heard of a camera that allows you to manually limit the Auto ISO range?

The camera chooses the ISO setting.

The camera chooses within limits that can be imposed by the camera designers or the user.

With my main camera, I use auto ISO almost all the time with it set to 102,400 mostly (I would prefer to set a maximum of about 80,000 but it only uses intermediates when set to the next level).

Even if you could manually select the ISO, using auto ISO,

smith-jones can manually select the range in which Auto ISO operates (within some limits).

why would you choose 102,400?

To help ensure a result that's of satisfactory brightness when the situation requires it.

That sounds ridiculous.

What sounds ridiculous to one person can be very useful to others. That happens a lot.

Setting the auto ISO limit is entirely different than manually adjusting the ISO.

Of course it's different. You did not say manually adjusting the ISO, and neither did anyone else. That would be an oxymoron when discussing Auto ISO. What you said is this:

"I've never seen or heard of a camera that would let you manually do anything when set to auto ISO."

"I use auto ISO almost all the time with it set to 102,400" Yes, that's ridiculous!

You missed the actual context of the full statement, which is that the upper limit is manually set to 102,400. Not ridiculous at all if a person's priority is to get satisfactory brightness when the situation requires it.

Obviously, I misunderstood the comment, but he never said he sets the upper limit to 102,400.

Reread his original comment and you might understand.

As I said in my original comment, you can't make any ISO adjustments when the camera is set to auto ISO.

Yes, you can set a maximum limit, but that's a setting, not an adjustment.

You can adjust ISO indirectly when using auto-ISO by adjusting one or several of - aperture, shutter speed or exposure compensation. Depending on what mode you are using.

Just like you may adjust shutter speed indirectly by adjusting ISO.

And, some people are capable of spinning just about anything.

It is how I often spin the wheels on my camera.

I often use auto-ISO in "manual mode". And sometimes I have to make compromises on exposure settings if I want to keep ISO below a certain level, unless I have set that as the upper limit on auto-ISO.

But in low light situations the best compromise between ISO and exposure may vary from shot to shot, so I may not want to limit highest ISO too much.

 

[alfn]

Is extended iso range the only camera spec more useless than native iso range? I doubt any photographer is going to think an iso of 100k on aps sensor has an acceptable amount of noise.

Depends on the camera, subject, photographer just like anything else.

There ARE cameras with even smaller sensors designed for ultra high ISOs (Canon made/make a few mainly video cameras both FF and smaller sensor that go to ISOs in the millions).

I am more worried about DR at higher ISOs than noise and some cameras are better at higher ISO than others and the other way around also applies.

Native ISO range is very useful for me a lot of the time.

I had thought "native" iso was the iso of the sensor to which no gain was applied. So it was a single number and not a "range".

This is a commonly put about idea, but is essentially wrong-headed.

ISO is not 'gain'

Correct. It is the effective sensitivity of the camera and should be referred to as the ISO sensitivity setting.

There are several types of 'gain' applied in a typical camera imaging chain. If 'no gain' is applied, the whole thing won't work.

 

[Ed B]

Extended ISO to me has been the range not normally set or used and sometimes called boosted where you have to choose it to use it.

Some cameras do not let you use the extended range in auto ISO

I've never seen or heard of a camera that would let you manually do anything when set to auto ISO.

You've never seen or heard of a camera that allows you to manually limit the Auto ISO range?

The camera chooses the ISO setting.

The camera chooses within limits that can be imposed by the camera designers or the user.

With my main camera, I use auto ISO almost all the time with it set to 102,400 mostly (I would prefer to set a maximum of about 80,000 but it only uses intermediates when set to the next level).

Even if you could manually select the ISO, using auto ISO,

smith-jones can manually select the range in which Auto ISO operates (within some limits).

why would you choose 102,400?

To help ensure a result that's of satisfactory brightness when the situation requires it.

That sounds ridiculous.

What sounds ridiculous to one person can be very useful to others. That happens a lot.

Setting the auto ISO limit is entirely different than manually adjusting the ISO.

"I use auto ISO almost all the time with it set to 102,400" Yes, that's ridiculous!

Just because YOU can not shoot at night does not mean others do not want to.

WHY is it ridiculous to set 102400 as the max and not ISO 6400? (some people NEVER shoot at ISO 6400 so for THEM even that as maximum would be crazy).

If I set 51600 ISO as my maximum but that is not quite enough what would YOU do? (put the camera away I am guessing).

Buy a better/faster lens.

I have had normal (as in not Elvis with a Yeti) photos published in newspapers at ISOs over 51600.

Again with other cameras I do not even go off base (I used to have a Canon G10 and it was a lovely camera but even at ISO 400, I would get greater DR with my A7s at 25600 and would be happier above that too.

It is just the MAXIMUM I am prepared to muse and does not mean every (or ANY) photos will be at 102400. I would prefer it used ISO 100 for every shot but once in a while I will need much higher....there are two higher settings that I do almost never use but even they are there for a reason.

 

[bobn2]

Is extended iso range the only camera spec more useless than native iso range? I doubt any photographer is going to think an iso of 100k on aps sensor has an acceptable amount of noise.

Depends on the camera, subject, photographer just like anything else.

There ARE cameras with even smaller sensors designed for ultra high ISOs (Canon made/make a few mainly video cameras both FF and smaller sensor that go to ISOs in the millions).

I am more worried about DR at higher ISOs than noise and some cameras are better at higher ISO than others and the other way around also applies.

Native ISO range is very useful for me a lot of the time.

I had thought "native" iso was the iso of the sensor to which no gain was applied. So it was a single number and not a "range".

This is a commonly put about idea, but is essentially wrong-headed.

ISO is not 'gain'

Correct. It is the effective sensitivity of the camera and should be referred to as the ISO sensitivity setting.

ISO says it is an 'exposure index'. The latest version defines 'photographic sensitivity' which is 'general term for numerical values based on the exposure at the focal plane of a DSC which produces a specified DSC image signal level, such as the standard output sensitivity or recommended exposure index'. The standard says exactly this about terminology:

'Note 1 to entry: In practise, the photographic sensitivity is often called the "sensitivity" or the "camera sensitivity". It is sometimes called the "ISO sensitivity", for historical reasons that date from ISO standards for photographic film cameras.

So, they don't say that it 'should' be referred to as the ISO sensitivity, they say that it is sometimes called that. One can almost sense the argument that went on in the committee about this. On one side the pressure to go with 'sensitivity' because that was common usage, on the other the technical guys who know that it has nothing to do with 'sensitivity' as it would be defined in other technical domains. Hence they say that it is referred to that way 'for historical reasons', exactly because they know that there are not technical reasons to do so.

 

[tony field]

Extended ISO to me has been the range not normally set or used and sometimes called boosted where you have to choose it to use it.

Some cameras do not let you use the extended range in auto ISO

I've never seen or heard of a camera that would let you manually do anything when set to auto ISO.

You've never seen or heard of a camera that allows you to manually limit the Auto ISO range?

The camera chooses the ISO setting.

The camera chooses within limits that can be imposed by the camera designers or the user.

With my main camera, I use auto ISO almost all the time with it set to 102,400 mostly (I would prefer to set a maximum of about 80,000 but it only uses intermediates when set to the next level).

Even if you could manually select the ISO, using auto ISO,

smith-jones can manually select the range in which Auto ISO operates (within some limits).

why would you choose 102,400?

To help ensure a result that's of satisfactory brightness when the situation requires it.

That sounds ridiculous.

What sounds ridiculous to one person can be very useful to others. That happens a lot.

Setting the auto ISO limit is entirely different than manually adjusting the ISO.

Of course it's different. You did not say manually adjusting the ISO, and neither did anyone else. That would be an oxymoron when discussing Auto ISO. What you said is this:

"I've never seen or heard of a camera that would let you manually do anything when set to auto ISO."

"I use auto ISO almost all the time with it set to 102,400" Yes, that's ridiculous!

You missed the actual context of the full statement, which is that the upper limit is manually set to 102,400. Not ridiculous at all if a person's priority is to get satisfactory brightness when the situation requires it.

Obviously, I misunderstood the comment, but he never said he sets the upper limit to 102,400.

Reread his original comment and you might understand.

As I said in my original comment, you can't make any ISO adjustments when the camera is set to auto ISO.

Yes, you can set a maximum limit, but that's a setting, not an adjustment.

You can adjust ISO indirectly when using auto-ISO by adjusting one or several of - aperture, shutter speed or exposure compensation. Depending on what mode you are using.

Just like you may adjust shutter speed indirectly by adjusting ISO.

If you adjust ISO manually, you limit the camera to exactly one ISO compliant exposure.

 

[bobn2]

Extended vs. native/base ISO-range has no real meaning. It is only a decision of the manufacturer which ISO-values they call extended and which are called normal/base/native/whatever.

A wild guess how they differentiate: Define some noise-level as acceptable, and call every setting that produces more noise 'extended'.

Jib, actually, as it was explained somewhere, there is a rhyme and reason to ISO.

Native ISO is the camera producing images using it's actual signal to noise ratios natively. The extended ISO's are not being created directly by the camera's shooting procedure but being completely generated by the algorithms in the computer if the camera could actually generate them as part of the shooting process.

I'm sure those much more technical than myself will correct me and lay out the process in much clearer detail. BUT it's not arbitrary!

I think that a fair amount of correction is needed, but scan through earlier posts in the thread and you'll find what you need. As it happens, the definition of what is an 'extended ISO' and what is not is indeed pretty much arbitrary.

There are many examples of cameras with the same sensors and electronics having different 'extended ISO ranges'. For instance, in the step from the Nikon D800 to Nikon D810, the lowest 'real ISO' went from 100 to 64, even though it was the same sensor and image processor. You'll find many more examples at the top end, where minor upgrades using the same sensor and processor have increased the highest 'real ISO'

 

[MoreCowbell]

. It appeals to me.

Sounds like a good enough reason to me

 

[alfn]

Is extended iso range the only camera spec more useless than native iso range? I doubt any photographer is going to think an iso of 100k on aps sensor has an acceptable amount of noise.

Depends on the camera, subject, photographer just like anything else.

There ARE cameras with even smaller sensors designed for ultra high ISOs (Canon made/make a few mainly video cameras both FF and smaller sensor that go to ISOs in the millions).

I am more worried about DR at higher ISOs than noise and some cameras are better at higher ISO than others and the other way around also applies.

Native ISO range is very useful for me a lot of the time.

I had thought "native" iso was the iso of the sensor to which no gain was applied. So it was a single number and not a "range".

This is a commonly put about idea, but is essentially wrong-headed.

ISO is not 'gain'

Correct. It is the effective sensitivity of the camera and should be referred to as the ISO sensitivity setting.

ISO says it is an 'exposure index'. The latest version defines 'photographic sensitivity' which is 'general term for numerical values based on the exposure at the focal plane of a DSC which produces a specified DSC image signal level, such as the standard output sensitivity or recommended exposure index'.

In other words the effective sensitivity of the camera (DSC).

The standard says exactly this about terminology:

'Note 1 to entry: In practise, the photographic sensitivity is often called the "sensitivity" or the "camera sensitivity". It is sometimes called the "ISO sensitivity", for historical reasons that date from ISO standards for photographic film cameras.

So the photographic sensitivity [of the camera] is often referred to as simply sensitivity or camera sensitivity for historical reasons. That makes sense when one is dealing with photographic standards created over a long period. Consistency is the whole point of standards.

So, they don't say that it 'should' be referred to as the ISO sensitivity, they say that it is sometimes called that.

Or camera sensitivity or simply sensitivity. All as defined by the ISO standard. Thus ISO sensitivity.

All the rest of your post is an elaborate fantasy created by you to justify calling the ISO sensitivity setting anything other than what it is.

 

[tony field]

Is extended iso range the only camera spec more useless than native iso range? I doubt any photographer is going to think an iso of 100k on aps sensor has an acceptable amount of noise.

Depends on the camera, subject, photographer just like anything else.

There ARE cameras with even smaller sensors designed for ultra high ISOs (Canon made/make a few mainly video cameras both FF and smaller sensor that go to ISOs in the millions).

I am more worried about DR at higher ISOs than noise and some cameras are better at higher ISO than others and the other way around also applies.

Native ISO range is very useful for me a lot of the time.

I had thought "native" iso was the iso of the sensor to which no gain was applied. So it was a single number and not a "range".

This is a commonly put about idea, but is essentially wrong-headed.

ISO is not 'gain'

Correct. It is the effective sensitivity of the camera and should be referred to as the ISO sensitivity setting.

ISO says it is an 'exposure index'. The latest version defines 'photographic sensitivity' which is 'general term for numerical values based on the exposure at the focal plane of a DSC which produces a specified DSC image signal level, such as the standard output sensitivity or recommended exposure index'.

In other words the effective sensitivity of the camera (DSC).

The standard says exactly this about terminology:

'Note 1 to entry: In practise, the photographic sensitivity is often called the "sensitivity" or the "camera sensitivity". It is sometimes called the "ISO sensitivity", for historical reasons that date from ISO standards for photographic film cameras.

So the photographic sensitivity [of the camera] is often referred to as simply sensitivity or camera sensitivity for historical reasons. That makes sense when one is dealing with photographic standards created over a long period. Consistency is the whole point of standards.

So, they don't say that it 'should' be referred to as the ISO sensitivity, they say that it is sometimes called that.

Or camera sensitivity or simply sensitivity. All as defined by the ISO standard. Thus ISO sensitivity.

All the rest of your post is an elaborate fantasy created by you to justify calling the ISO sensitivity setting anything other than what it is.

Bob's comments are quite correct.

If you are interested in a much more complete description read this CIPA DC-004 document which gives a complete definition of SOS & REI as well including calculations

https://www.google.com/search?q=cip...msung-nf-rev1&sourceid=chrome-mobile&ie=UTF-8

--
Charles Darwin: "ignorance more frequently begets confidence than does knowledge."
tony

 

[bobn2]

Is extended iso range the only camera spec more useless than native iso range? I doubt any photographer is going to think an iso of 100k on aps sensor has an acceptable amount of noise.

Depends on the camera, subject, photographer just like anything else.

There ARE cameras with even smaller sensors designed for ultra high ISOs (Canon made/make a few mainly video cameras both FF and smaller sensor that go to ISOs in the millions).

I am more worried about DR at higher ISOs than noise and some cameras are better at higher ISO than others and the other way around also applies.

Native ISO range is very useful for me a lot of the time.

I had thought "native" iso was the iso of the sensor to which no gain was applied. So it was a single number and not a "range".

This is a commonly put about idea, but is essentially wrong-headed.

ISO is not 'gain'

Correct. It is the effective sensitivity of the camera and should be referred to as the ISO sensitivity setting.

ISO says it is an 'exposure index'. The latest version defines 'photographic sensitivity' which is 'general term for numerical values based on the exposure at the focal plane of a DSC which produces a specified DSC image signal level, such as the standard output sensitivity or recommended exposure index'.

In other words the effective sensitivity of the camera (DSC).

That depends entirely on what you mean by 'effective sensitivity'. It requires an unusual interpretation of the word 'sensitivity' to make it mean the same as ISO's own word salad. Even more so when you actually read the standard. For instance the 'specified DSC signal level' under the recommended exposure index is 'the arithmetic mean focal plane exposure, expressed in lux-seconds, recommended by the DSC provider'. That is, the 'specified signal level' is whatever the camera manufacturer chooses to recommend.

I think you'll have a hard time finding any other 'sensitivity' defined as 'whatever the manufacturer recommends'. The 'standard output sensitivity' is little better. That says that the specified signal level is 'equal to 461/1000 x Omax, where Omax is the maximum output value of the digital system'. So, even if one thinks that 'sensitivity' is synonymous with 'responsivity', this is a standard where the 'effective sensitivity' might be changed simply by changing the value of a number (Omax) in software.

Simply, this definition of 'sensitivity' aligns with no other usage of the word in a technical domain.

The standard says exactly this about terminology:

'Note 1 to entry: In practise, the photographic sensitivity is often called the "sensitivity" or the "camera sensitivity". It is sometimes called the "ISO sensitivity", for historical reasons that date from ISO standards for photographic film cameras.

So the photographic sensitivity [of the camera] is often referred to as simply sensitivity or camera sensitivity for historical reasons. That makes sense when one is dealing with photographic standards created over a long period. Consistency is the whole point of standards.

It also makes sense if you're looking for agreement on a committee of diverse interests and views.

So, they don't say that it 'should' be referred to as the ISO sensitivity, they say that it is sometimes called that.

Or camera sensitivity or simply sensitivity. All as defined by the ISO standard. Thus ISO sensitivity.

They say precisely what they say, that it is sometimes called sensitivity, not that it should be called sensitivity.

All the rest of your post is an elaborate fantasy created by you to justify calling the ISO sensitivity setting anything other than what it is.

If there had been a technical reason for calling it 'ISO sensitivity' they would have given it, in fine detail and with formulae that explained it. The very fact that they say that it is for historical reasons means that there is no technical reason, but a historical one.

 

[JohnSil]

Extended ISO to me has been the range not normally set or used and sometimes called boosted where you have to choose it to use it.

Some cameras do not let you use the extended range in auto ISO

I've never seen or heard of a camera that would let you manually do anything when set to auto ISO.

You've never seen or heard of a camera that allows you to manually limit the Auto ISO range?

The camera chooses the ISO setting.

The camera chooses within limits that can be imposed by the camera designers or the user.

With my main camera, I use auto ISO almost all the time with it set to 102,400 mostly (I would prefer to set a maximum of about 80,000 but it only uses intermediates when set to the next level).

Even if you could manually select the ISO, using auto ISO,

smith-jones can manually select the range in which Auto ISO operates (within some limits).

why would you choose 102,400?

To help ensure a result that's of satisfactory brightness when the situation requires it.

That sounds ridiculous.

What sounds ridiculous to one person can be very useful to others. That happens a lot.

Setting the auto ISO limit is entirely different than manually adjusting the ISO.

"I use auto ISO almost all the time with it set to 102,400" Yes, that's ridiculous!

So Ed, why is it ridiculous to set the ISO to 102k? For a savvy photographer that’s ready for anything that’s a very smart move! Un-savvy photographers set it to 6400 and miss half the shots!!!

John

 

[MoreCowbell]

Extended ISO to me has been the range not normally set or used and sometimes called boosted where you have to choose it to use it.

Some cameras do not let you use the extended range in auto ISO

I've never seen or heard of a camera that would let you manually do anything when set to auto ISO.

You've never seen or heard of a camera that allows you to manually limit the Auto ISO range?

The camera chooses the ISO setting.

The camera chooses within limits that can be imposed by the camera designers or the user.

With my main camera, I use auto ISO almost all the time with it set to 102,400 mostly (I would prefer to set a maximum of about 80,000 but it only uses intermediates when set to the next level).

Even if you could manually select the ISO, using auto ISO,

smith-jones can manually select the range in which Auto ISO operates (within some limits).

why would you choose 102,400?

To help ensure a result that's of satisfactory brightness when the situation requires it.

That sounds ridiculous.

What sounds ridiculous to one person can be very useful to others. That happens a lot.

Setting the auto ISO limit is entirely different than manually adjusting the ISO.

"I use auto ISO almost all the time with it set to 102,400" Yes, that's ridiculous!

So Ed, why is it ridiculous to set the ISO to 102k? For a savvy photographer that’s ready for anything that’s a very smart move! Un-savvy photographers set it to 6400 and miss half the shots!!!

John

I don't have any interest in participating in this pissin match, but I was curious about ISO 102,400 from a purely intellectual point of view, I had the camera setting on the desk next to the computer, and I needed to waste a few minutes while the wife brought me another beer

Three singularly uninteresting images shot at 102,400 on a D6. Raw image Photoshop saved as a tiff and then converted to jpeg. All default settings.

This probably isn't something I'd do with any regularity, but on the occasions we visit the interiors of ruins castles and such, it's arguable that the results might be better, on certain subjects, than no results at all.

Or not, depending on your opinion. As I say I don't have a dog in this fight.







--
Personal, non commercial vacation snapshots at
https://www.castle-explorers.com

 

[Quarkcharmed]

Extended ISO to me has been the range not normally set or used and sometimes called boosted where you have to choose it to use it.

Some cameras do not let you use the extended range in auto ISO

I've never seen or heard of a camera that would let you manually do anything when set to auto ISO.

You've never seen or heard of a camera that allows you to manually limit the Auto ISO range?

The camera chooses the ISO setting.

The camera chooses within limits that can be imposed by the camera designers or the user.

With my main camera, I use auto ISO almost all the time with it set to 102,400 mostly (I would prefer to set a maximum of about 80,000 but it only uses intermediates when set to the next level).

Even if you could manually select the ISO, using auto ISO,

smith-jones can manually select the range in which Auto ISO operates (within some limits).

why would you choose 102,400?

To help ensure a result that's of satisfactory brightness when the situation requires it.

That sounds ridiculous.

What sounds ridiculous to one person can be very useful to others. That happens a lot.

Setting the auto ISO limit is entirely different than manually adjusting the ISO.

"I use auto ISO almost all the time with it set to 102,400" Yes, that's ridiculous!

So Ed, why is it ridiculous to set the ISO to 102k? For a savvy photographer that’s ready for anything that’s a very smart move! Un-savvy photographers set it to 6400 and miss half the shots!!!

With the cameras that can do ISO 102K, you can shoot at ISO 6400 and most likely you'll be fine, providing you shoot raw and use some strong denoise software.