Ysarex Loc: St. Louis

Your test is one of your meaningless diversions. All it will show is what we already know -- that a common implementation of ISO is to boost the signal from the sensor either analog or digitally and that implementation of course alters the raw files. I've acknowledged that and early in the thread explained it and stressed the change to the raw files. I've never said otherwise.

But you said: "Any ISO setting above base will affect the raw file..."

And again you said in response to BebuLamar's question:
"Correct so long as you are above base ISO." BebuLamar's question is clear: "...must be different." "Must" doesn't leave room for options. And the fact is the raw file will or will not be different depending on how the ISO change is implemented. Options exist that will not change the raw file.

Of course I presented examples which prove you wrong. https://www.uglyhedgehog.com/t-609317-16.html#10495225

Your fabricated accusations that I tampered with what I presented are entirely dishonest but expected from you. You know damn well all cameras embed a copy of the JPEG in the raw file. You're using that dishonestly as a lame excuse because your juvenile ego can't stand the fact that you are wrong. You are proven wrong and you are pathetic.

Joe

selmslie Loc: Fernandina Beach, FL, USA

Double posts? Getting a little nervous? I guess I'll just put you out of your misery.

As it turns out, five one stop increments were more than enough. It will look pretty obvious to anyone with a functioning brain any experience with exposure.

So that proves that you are wrong, a liar and a fool for thinking you could deceive us.

If you continue to claim that this is not accurate then you are worse than a fool.

ISO 100

(Download)

ISO 200

(Download)

ISO 400

(Download)

ISO 800

(Download)

ISO 1600

(Download)

ISO 100

(Download)

ISO 200

(Download)

ISO 400

(Download)

ISO 800

(Download)

ISO 1600

(Download)

roy4711 Loc: Spring Valley IL.

I got it thank you.

Ysarex Loc: St. Louis

It only proves that what I described earlier: https://www.uglyhedgehog.com/t-609317-3.html#10480581
is correct and is one possible option as I correctly noted.

To claim it proves me wrong is to engage is a childish logic fallacy: "My car runs on gasoline therefore all cars run on gasoline." Most children get past that kind of faulty thinking.



You are well aware that all camera manufacturers embed copies of the JPEG in the raw files. Your dishonest claim that I was deceitful because I used the embedded JPEG is lame and pathetic.



I have never claimed what these examples show is not accurate. You show me where I ever said that. In fact I described accurately what these examples show: https://www.uglyhedgehog.com/t-609317-3.html#10480581

If you can't show where I made such a claim then of course your wrong again.

You said: "Any ISO setting above base will affect the raw file..."

You are proven wrong:

https://www.uglyhedgehog.com/t-609317-16.html#10495225
https://www.uglyhedgehog.com/t-609317-13.html#10491484
https://www.uglyhedgehog.com/t-609317-13.html#10492475

That's hard evidence for which you have no rebuttal.

It is also hard evidence that your childish logic fallacy presented here is just that and it goes hand in hand with your pathetic accusations of deceit.

You stay proven wrong because you can't refute hard evidence. I gave you the raw files.

Joe

BebuLamar

You say if the sensor is given identical exposure and changing the ISO doesn't affect the RAW file is that what you said? If so what does changing the ISO do?

selmslie Loc: Fernandina Beach, FL, USA

Anyone can replicate my example with their own camera using RawDigger to view the histograms. https://www.uglyhedgehog.com/t-609317-17.html#10495445

You have not explained why that also worked for you for (A) https://www.uglyhedgehog.com/t-609317-14.html#10493326 where the raw histograms are different but not for (B) https://www.uglyhedgehog.com/t-609317-16.html#10495225 where the raw histograms are the same.

The only explanation I have left is that you manipulated the results for (B) after you captured the image. How you did that is not relevant. But since nobody is going to be able to reproduce your results until you come clean, your demonstration has absolutely no validity. It demonstrates nothing useful. It is misleading, even fraudulent.

Ysarex Loc: St. Louis

That's one option, but not the only option.

Take two photos at the same exposure (shutter speed and f/stop set manually).
Take the first photo at base ISO -- say 100.
Take the second photo with the ISO raised -- 200.

The only change then is the increase in the ISO from base 100 to 200. What does/can the camera do in response to the ISO change?

a) The camera can apply analog gain to the sensor signal before the raw file is created. This would produce two different raw files.

b) The camera can use digital scaling during the creation of the raw file to raise the values stored in the raw file. This would produce two different raw files.

The camera can use a combination of both a) and b) above. This would produce two different raw files.

c) The camera can apply the ISO indicated lightening of the image in the camera image processor to create the final JPEG after the raw file has been created. This would produce two identical raw files.

The camera manufacturer is free to use any method or combination of methods as long as the final image result is achieved.

In the example below the camera (Canon G7xmkii) used method c) listed above and the result is one JPEG brighter than the other as the ISO change would require but two identical raw files. This is a standard compliant application of ISO supported by the camera used in the example. The critical point which gets to your second question is that the ISO standard does not specify implementation -- it only specifies the final result.

https://www.uglyhedgehog.com/t-609317-16.html#10495225

What ISO does is establish standard measuring methodologies for determining the brightness in the camera output image -- typically JPEG -- that results from a measured exposure.

Joe

BebuLamar

I do not have a camera that uses method c as none of my camera produce identical RAW files with same exposure and different ISO. However, with a camera that uses method c then there is no need to set the ISO.

Ysarex Loc: St. Louis

Asked and answered. I already told you I answered that in a reply to srt101fan:
https://www.uglyhedgehog.com/t-609317-15.html#10494026

I just again explained it in an answer to BebuLamar: https://www.uglyhedgehog.com/t-609317-17.html#10496888



You have the raw files and you have an answer. And you were wrong to pontificate that all cameras work the same way. If you learn what ISO is you can read the response I just posted for BebuLamar: https://www.uglyhedgehog.com/t-609317-17.html#10496888 and the explanation is simple. All cameras do not implement ISO using only one method.



My results can be reproduced by anyone using the same cameras I used. You just have to understand how they work. Both my Canon and Fuji cameras provide options to apply an ISO change without using analog sensor gain or digital scaling that would alter the raw file. Don't you have a Fuji camera? Maybe you have an old model.

Joe

Ysarex Loc: St. Louis

For a camera using method c) it is still necessary to set the ISO because the ISO value still determines the lightness in the output image. The same constraints we struggle with concerning action stopping shutter speeds and f/stops controling DOF apply to a camera using method c) and so the metering control we get through ISO still applies to a camera using method c).

Subtle variations in the final output image can result from the method applied and more and more we are getting cameras from the manufacturers that provide us with choice. Options that use method c) are less common but increasingly common. Typically they are employed to address a specific need and exist in a camera along with methods a) and b). My Canon camera is capable of all three. Again the point is that ISO is not defined by the camera implementation but only by the final output image.

Joe

BebuLamar

If the RAW files are the same you can produce the same image.

Ysarex Loc: St. Louis

Absolutely.

I'm exclusively a raw shooter. I can own a camera for years and never set the camera to save a JPEG. If you're like me and focus predominately on shooting raw files it can be kind of weird to take in the fact that the ISO standard does not apply to raw files. In the latest 2019 revision they made a point of stressing that. We still use ISO as we work with raw files (that's confusing if it doesn't apply) but what the standard specifies is the output image from the camera processor.

Joe

selmslie Loc: Fernandina Beach, FL, USA

You are capturing the raw image at one ISO and producing the JPEG as though the ISO were different.

We all do this when we bring an image onto the computer and move the Exposure slider during the raw conversion. DUH!

You can also do that to a JPEG with in-camera post processing but that makes your option "c" totally irrelevant to this discussion.

selmslie Loc: Fernandina Beach, FL, USA

They do so long as you are above base ISO.

You had to post process the raw data to change the brightness of the JPEG. You pretended otherwise for 17 pages.

Your intent was not to educate, just to draw attention to yourself.

Ysarex Loc: St. Louis

Absolutely not! And the images prove that. RawDigger likewise proves that. Open the raw files in RawDigger and show me where RawDigger identifies both images captured at the same ISO.

In this example: https://www.uglyhedgehog.com/t-609317-16.html#10495225

The first image was captured with the ISO on the camera set to 125 and the second image was captured with the ISO set to 250. Prove otherwise.



Irrelevant. ISO applies to cameras not post processing software. DUH!



Also irrelevant. That's also post processing and you have the raw files which indicate I didn't do that. The thread topic is ISO.

You have been proven wrong.

Joe