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ISO is not fake and here is the standards document
- Thread starter ElhanDobriv
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Michael Fryd
Forum Pro
But there isn't a definition of what that image should look like. There are a range of images that are correct representations of the raw file.
The image you get out of Adobe Camera Raw will differ from the image you get out of the manufacture's software. There isn't a standard that suggests one of them is "correct" and the other is not.
It's worse than that. There are multiple rendering routines for each concrete raw format. There is no agreement as to which is correct and which is not.
If everyone thought that only the manufacture's software was correct, there would be no market for other software.
Even if you think the manufacture's software is the only correct software, then which set of options is the one that yields the correct image? For instance, Canon has an option called "highlight tone priority". The raw data is the same whether the option is on or off. Does changing this option in the rendering software produce an incorrect result?
On the other hand there is a well accepted standard on exactly what color to render each RGB pixel value in a JPEG file. Any other color is an incorrect result.
Yes, most people don't have a fully calibrated workflow, and therefore the rendered colors are usually close, but not always exact. This deviation from the ideal is an error.
With raw files, there is no agreed upon standard for what color each pixel should be. Therefore we can't say whether any particular rendering is correct. At best we can say that it looks pleasingly close to what we expect.
Ideally yes, but in practice no. Last time I checked, there were differences between camera produced JPEGs and JPEGs produced by Canon's DPP software. My understanding was that the camera does not have as much computing power as a typical home computer. In order to maintain acceptable performance, the camera's processing takes some shortcuts to speed things up. The results look close to what DPP produces, but there are not quite the same.
Michael Fryd
Forum Pro
That's an interpretation of the data. There are many other ways of expressing the data that produce different results, but are also reasonable interpretations of the data.
For instance, the spectral response of the red, green and blue pixels in the above image likely don't match the filters in front of the various pixels.
sybersitizen
Forum Pro
So you think it's not a picture?That's an interpretation of the data. There are many other ways of expressing the data that produce different results, but are also reasonable interpretations of the data.
For instance, the spectral response of the red, green and blue pixels in the above image likely don't match the filters in front of the various pixels.
It is a picture but it is not the RAW data. The latter looks like this: 0010110110100...So you think it's not a picture?That's an interpretation of the data. There are many other ways of expressing the data that produce different results, but are also reasonable interpretations of the data.
For instance, the spectral response of the red, green and blue pixels in the above image likely don't match the filters in front of the various pixels.
tony field
Forum Pro
Rawtherapee can show the grgb hidden image as an image for all pixels
sybersitizen
Forum Pro
I think so too.It is a pictureSo you think it's not a picture?That's an interpretation of the data. There are many other ways of expressing the data that produce different results, but are also reasonable interpretations of the data.
For instance, the spectral response of the red, green and blue pixels in the above image likely don't match the filters in front of the various pixels.
If that's the criterion for calling something a picture, then no digital file of any kind is a picture either - not even a JPEG.
Then what's the point of anyone singling out RAW files to say they're not pictures?
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Why would you write this after I answered the same objection 10-15 min ago?
Because they are not?
Michael Fryd
Forum Pro
That's a reasonable question.
Each ISO setting has a corresponding expected exposure. If you meter a scene, and your meter says that at f/8 and 1/60 you should use ISO 400, then the exposure you get a f/8 and 1/60 is likely appropriate for ISO 400.
When you set the ISO on a digital camera, the camera will expect an exposure that's appropriate for the selected ISO.
Some cameras will make internal configuration adjustments based on that expected exposure.
It is possible for a camera manufacture to separate out those configuration adjustments from the ISO setting, but that's not how typical cameras work.
From a practical matter, setting the ISO value is how you adjust those config settings.
Setting the ISO also sets a target exposure for the camera's metering system, but there is no requirement that you have to make the camera's meter happy.
The camera manufacturer doesn't know what you are pointing the camera at. You can let the camera's meter measure the scene, and use Auto-ISO, or you can manually inform the camera what exposure to expect by setting a specific ISO.
Not with modern cameras.
Assume you are in a position where motion blur concerns require you to use a shutter of 1/60, and you have the lens wide open at f/2.8
You get a camera produced JPEG with reasonable lightness when you set the ISO to 1600.
You could set the camera to ISO 100, and adjust the lightness when processing. If the results were the same, then there would be no advantage to ISO settings for raw shooters.
It's true that on some cameras, there would be no difference, but on some cameras, the image shot at ISO 1600 would have less noise. This is because some cameras add less noise to the image when set to ISO 1600 than when set to ISO 100. If you have one of these cameras (and many popular cameras fall into this category) then the ISO setting is quite useful to a raw shooter.
If you are using Auto-ISO, the ISO chosen by the camera is useful, and it gives you a rough idea of the exposure you are getting, and therefore a rough idea of how noisy the image will look. If you think the image will have more noise than you find acceptable, you can look at various options for raising exposure (adding more light to the scene, using a tripod for longer shutter, switching to a lens with a wider aperture, etc.) This is helpful even to those who shoot raw.
sybersitizen
Forum Pro
I don't always read everything in every thread. Looking back, I guess you mean this:Why would you write this after I answered the same objection 10-15 min ago?I think so too.It is a pictureSo you think it's not a picture?That's an interpretation of the data. There are many other ways of expressing the data that produce different results, but are also reasonable interpretations of the data.
For instance, the spectral response of the red, green and blue pixels in the above image likely don't match the filters in front of the various pixels.
If that's the criterion for calling something a picture, then no digital file of any kind is a picture either - not even a JPEG.
Then what's the point of anyone singling out RAW files to say they're not pictures?
"JPEGs correspond to output pictures. RAWs correspond to an input (of a scene)."
But you yourself say both varieties produce pictures, and that was the question.
Then it's better to say no digital file is a picture to cover the facts without appearing to be discriminatory.
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tony field
Forum Pro
I disagree
They seem to be images images in GRGB rather than RGB. Look at the options in Rawtherapee which gives an "image" of the raw data.
That was after I said that JPEG corresponds to a picture by some standards, both the JPEG one and the color space one.I don't always read everything in every thread. Looking back, I guess you mean this:Why would you write this after I answered the same objection 10-15 min ago?I think so too.It is a pictureSo you think it's not a picture?That's an interpretation of the data. There are many other ways of expressing the data that produce different results, but are also reasonable interpretations of the data.
For instance, the spectral response of the red, green and blue pixels in the above image likely don't match the filters in front of the various pixels.
If that's the criterion for calling something a picture, then no digital file of any kind is a picture either - not even a JPEG.
Then what's the point of anyone singling out RAW files to say they're not pictures?
"JPEGs correspond to output pictures. RAWs correspond to an input (of a scene)."
No, I did not say that. I said that what you posted was a picture. And I said that it was not the RAW.
The standards used to encode a picture are responsible for the discrimination.
Michael Fryd
Forum Pro
I think it is a picture inspired by the raw data. It is not the picture represented by the raw data.So you think it's not a picture?That's an interpretation of the data. There are many other ways of expressing the data that produce different results, but are also reasonable interpretations of the data.
For instance, the spectral response of the red, green and blue pixels in the above image likely don't match the filters in front of the various pixels.
There are many other ways of visualizing the data in a raw file. A more common way would be to use full color for each pixel.
So the above is a picture visualizing the raw data. But it is not the only one.
With a JPEG, there is a single correct rendering.
They may seem that way but they are not. They represent sensor data, with a black point added, encoded linearly, each channel scaled somehow depending on the sensor, those RGB are not the ones we use in any standard color space, and they have that Bayer structure. There is no inherent lightness, for starters.
Good use of the quotation marks.
sybersitizen
Forum Pro
What I actually ended up posting is this: But you yourself say both varieties produce pictures, and that was the question.
If you didn't say that either, okay, I retract it and will not comment on what you said, or refer to it.
Both can be considered pictures encoded as data, although one picture might look more familiar than the other.
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sybersitizen
Forum Pro
Good. That's all I'm asking here.I think it is a picture inspired by the raw data.So you think it's not a picture?That's an interpretation of the data. There are many other ways of expressing the data that produce different results, but are also reasonable interpretations of the data.
For instance, the spectral response of the red, green and blue pixels in the above image likely don't match the filters in front of the various pixels.
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No, that was not the question, and you can produce a lot of pictures from the same file. A gray one, for example, why not.
No, only one of them has a standard to tell you what picture to get.
tony field
Forum Pro
For good reason! It seems to decode the TIFF image block containing the raw data in a linear manner with an appropriate pixel colour. Give it a try and analyze the result.They may seem that way but they are not. They represent sensor data, with a black point added, encoded linearly, each channel scaled somehow depending on the sensor, those RGB are not the ones we use in any standard color space, and they have that Bayer structure. There is no inherent lightness, for starters.
Good use of the quotation marks.
--
Charles Darwin: "ignorance more frequently begets confidence than does knowledge."
tony
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Michael Fryd
Forum Pro
Here's the difference.
With a JPEG, I can tell you exactly what picture corresponds to the data.
With a RAW file, I can a bunch of images that visualize the data. But there is no standard to determine which (if any) is the picture that the raw data represents.
.
The JPEG data specifies an image.
The RAW data suggests a family of images.
sybersitizen
Forum Pro
That's not the question either.
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