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Could you actually see photos made from RAW files?
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Could you actually see photos made from RAW files?
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Could you actually see photos made from RAW files?
In article
, wrote: I do, however, wonder that by working on raw format, one will end up spending much more time post processing after the photos are taken. that's absolutely false. with modern raw converters, there is *no* time penalty for shooting raw, unless of course, you want to spend a lot of time tweaking it. quite often, the default parameters are good enough, with maybe only a minor tweak needed. with some raw converters (e.g., lightroom), there isn't even a difference in the workflow between raw or jpeg - you just give it images from the camera and see the results on screen, adjust as needed, print or upload to the 'net. it's same amount of time either way, but if you shoot raw, the results will generally be better than if you shoot jpeg. that's why it's somewhat of a waste to shoot raw+jpeg. I just have one question - if you take a photo which was out of focus, could you actually make it in focus when you have the raw files? not really. it can be possible to undo it a little with very sophisticated modeling of the lens and a lot of expensive software though. |
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Could you actually see photos made from RAW files?
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Could you actually see photos made from RAW files?
Eric Stevens wrote:
Floyd, I suspect you have been smoking something which is not good for you. Subject to statistical error limitations, there is a one to one correspondence between the source image and the RAW file. One can be converted to the other using the rules inherent in the camera's software. What do you mean by "the source image"? Pehraps you need to study up on what a raw data file is, and what a JPEG or TIFF image file is? Do you know, for example, why the word "interpolation" (see a good dictionary) is used to describe the process of converting raw sensor data to an image format? The data in the RAW file can't be restructured to make a different image without changing the data. That is not true. In fact there is far more data in a raw file than is needed to make an image. Likewise it is possible to emphasize different parts of the data in different ways to get different images. That is exactly what white balance is, for example. It's also true that while I said that at least 9 sensor locations are used to generate each pixel, there are several variations on ways to interpolate the data that use more than 9. Each method is different. Did you read, and understand, the following few paragraphs? A JPEG or TIFF file contains an image. The RAW file contains data to make an image. For example, each "sensal" location on the sensor does *not* translate to a single pixel in the resulting image. Instead the data from at least 9 different sensors locations is used to determine the Red, Green, and Blue values for a single pixel. The process where all of that data is interpolated is called "raw conversion", and is much the same as converting a pile of nails and boards into a house. If you understood that, then the above part that you objected to should have made sense. If not, tell me what you think it all is and I'll try to explain the significance in a way that is directed at your response (rather than at the OP for this thread). -- Floyd L. Davidson http://www.apaflo.com/floyd_davidson Ukpeagvik (Barrow, Alaska) |
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Could you actually see photos made from RAW files?
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Could you actually see photos made from RAW files?
Eric Stevens wrote:
On Sat, 30 May 2009 21:32:27 -0800, (Floyd L. Davidson) wrote: Eric Stevens wrote: Floyd has failed to point out that at this point he has omitted a great deal of previous text. I know he has been around more than long enough to know that this is not the right thing to do. I've been posting on Usenet for over 20 years Eric, and I do know that snipping out the part not being commented on is the right way to edit an article before posting. When are *you* going to learn that? you. Subject to statistical error limitations, there is a one to one correspondence between the source image and the RAW file. One can be converted to the other using the rules inherent in the camera's software. What do you mean by "the source image"? That which is projected onto the sensor by the lens. Then your statements above are patently silly on their face. The raw data is a sampled set drawn from the projected image. The projected image cannot ever be recreated in its entirety, nor can the samples even be recreated with precision. Perhaps you need to explain what you are trying to say, preferably without the aid of whatever it is you have snipped from this article before replying. I certainly have not used text that isn't here, and don't see how that would be possible! Do you know, for example, why the word "interpolation" (see a good dictionary) is used to describe the process of converting raw sensor data to an image format? I know very well what is meant by the word 'interpolation' and the manner in which this is carried out has nothing whatsoever to do with the relationship between the source image and the RAW file except to the extent that it is determined by the rules inherent in the camera's software. You said the "source image" is what is projected on the sensor. Interpolation of course is the method by which the sensor data is converted to an image format for viewing. Two very distinctly separate relationships. The data in the RAW file can't be restructured to make a different image without changing the data. That is not true. In fact there is far more data in a raw file than is needed to make an image. Likewise it is possible to emphasize different parts of the data in different ways to get different images. That is exactly what white balance is, for example. And a change in the white balance involves a change in the interpreted RAW data: i.e. the white balance can only be changed by changing the raw data. It is quite possible to change the raw data to effect while balance, but it isn't normally done that way (Nikon, for example, has hinted that they might be doing exactly that in hardware). What is changed is the interpolation of the data when creating an image format. The raw data is not changed, and the raw file stays exactly the same. The way the data is manipulated during interpolation changes. Regardless of that, it is rather easy to demonstrate that the raw data is not changed in order to adjust white balance. Merely convert a RAW file to a JPEG image and then, using only the JPEG image (which contains vastly less data that the RAW file), use an editor to change the white balance and write a new JPEG file with a different white balance. The raw data is not even used, much less changed. It's also true that while I said that at least 9 sensor locations are used to generate each pixel, there are several variations on ways to interpolate the data that use more than 9. Each method is different. The sensor locations are irrelevant. The RAW data is derived from the sensors by rules which are determined by the manufacturer of the camera. False. Every different raw converter design uses a different set of "rules". Coffin's dcraw.c uses one set, Nikon uses another, and several other raw converters are different from both of those. The sensor locations are hardly irrelevant either. As I said, at least *nine* of them are used to generate each pixel in the resulting image, and you can be assured the location is relevant! It isn't one pixel and then 8 other randomly chosen locations... it's a group of 9 (or more). The signals generated by the sensors are determined by the rules inherent in the camera's software. They are determined by rules inherent in the camera's hardware. The sensor is not manipulated by software other than clearing it and reading it. A given amount of light on one sensor locations produces *exactly* the same output from the sensor regardless of the camera's software. As I have already said, there is a one to one correspondence between the source image and the RAW file. You can say that all you like, but it still requires at least *nine* different sensor locations to generate data for each pixel of the resulting image. It is not a one to one relationship. You don't have a choice of RAW files for a given image. Nor do you have a choice of images for a given RAW file. But you have a choice of an infinite number of resulting images when the camera raw data is interpolated. None of them are exactly the same as your "source image" that was projected onto the sensor. If you understood that, then the above part that you objected to should have made sense. If not, tell me what you think it all is and I'll try to explain the significance in a way that is directed at your response (rather than at the OP for this thread). JPEGs, TIFFs and RAW files all contain data required to create an image. A JPEG or TIFF contains the data for a single image. A RAW file contains information for something approaching an infinite number of images. The principal difference is that the format of JPEGs and TIFFs are independent of of the camera which created them while RAW files are not. The JPEG and TIFF images are no more, or less, independent of the camera than the RAW data. -- Floyd L. Davidson http://www.apaflo.com/floyd_davidson Ukpeagvik (Barrow, Alaska) |
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Could you actually see photos made from RAW files?
On Sun, 31 May 2009 03:10:56 -0800, (Floyd L.
Davidson) wrote: Eric Stevens wrote: On Sat, 30 May 2009 21:32:27 -0800, (Floyd L. Davidson) wrote: Eric Stevens wrote: Floyd has failed to point out that at this point he has omitted a great deal of previous text. I know he has been around more than long enough to know that this is not the right thing to do. I've been posting on Usenet for over 20 years Eric, and I do know that snipping out the part not being commented on is the right way to edit an article before posting. I wasn't complaining about you deleting the text. It was your failure to point out that you have deleted text, which I criticised. When are *you* going to learn that? When are you going to mark your deletions. you. Subject to statistical error limitations, there is a one to one correspondence between the source image and the RAW file. One can be converted to the other using the rules inherent in the camera's software. What do you mean by "the source image"? That which is projected onto the sensor by the lens. Then your statements above are patently silly on their face. The raw data is a sampled set drawn from the projected image. The projected image cannot ever be recreated in its entirety, nor can the samples even be recreated with precision. What do you think I meant by 'statisticsl error limitations'? Perhaps you need to explain what you are trying to say, preferably without the aid of whatever it is you have snipped from this article before replying. I certainly have not used text that isn't here, and don't see how that would be possible! Yet you claim it is possible to create an image from data that isn't there! Do you know, for example, why the word "interpolation" (see a good dictionary) is used to describe the process of converting raw sensor data to an image format? I know very well what is meant by the word 'interpolation' and the manner in which this is carried out has nothing whatsoever to do with the relationship between the source image and the RAW file except to the extent that it is determined by the rules inherent in the camera's software. You said the "source image" is what is projected on the sensor. Interpolation of course is the method by which the sensor data is converted to an image format for viewing. That's part of what I meant when I wrote of "the rules inherent in the camera's software". Two very distinctly separate relationships. The data in the RAW file can't be restructured to make a different image without changing the data. That is not true. In fact there is far more data in a raw file than is needed to make an image. Likewise it is possible to emphasize different parts of the data in different ways to get different images. That is exactly what white balance is, for example. And a change in the white balance involves a change in the interpreted RAW data: i.e. the white balance can only be changed by changing the raw data. It is quite possible to change the raw data to effect while balance, but it isn't normally done that way (Nikon, for example, has hinted that they might be doing exactly that in hardware). .... and therefore it is a different image. But nevertheless there is only the one image which can be created from a set of unmodified raw data. What is changed is the interpolation of the data when creating an image format. The raw data is not changed, and the raw file stays exactly the same. The way the data is manipulated during interpolation changes. An interpolated data set is a new data set. Regardless of that, it is rather easy to demonstrate that the raw data is not changed in order to adjust white balance. Merely convert a RAW file to a JPEG image and then, using only the JPEG image (which contains vastly less data that the RAW file), use an editor to change the white balance and write a new JPEG file with a different white balance. The raw data is not even used, much less changed. But only the one JPEG can be created from the RAW data providing the rules of the transformation do not change. It's also true that while I said that at least 9 sensor locations are used to generate each pixel, there are several variations on ways to interpolate the data that use more than 9. Each method is different. The sensor locations are irrelevant. The RAW data is derived from the sensors by rules which are determined by the manufacturer of the camera. False. Every different raw converter design uses a different set of "rules". Coffin's dcraw.c uses one set, Nikon uses another, and several other raw converters are different from both of those. But they are working on the camera's saved RAW file, not the relationship between what the sensor sees and the saved RAW file. The sensor locations are hardly irrelevant either. As I said, at least *nine* of them are used to generate each pixel in the resulting image, and you can be assured the location is relevant! It isn't one pixel and then 8 other randomly chosen locations... it's a group of 9 (or more). So? The signals generated by the sensors are determined by the rules inherent in the camera's software. They are determined by rules inherent in the camera's hardware. The sensor is not manipulated by software other than clearing it and reading it. A given amount of light on one sensor locations produces *exactly* the same output from the sensor regardless of the camera's software. I should have said "The signals generated by the sensors are -interpreted- by the rules inherent in the camera's software". To that extent they are 'determined'. As I have already said, there is a one to one correspondence between the source image and the RAW file. You can say that all you like, but it still requires at least *nine* different sensor locations to generate data for each pixel of the resulting image. It is not a one to one relationship. I see the problem. You misunderstand what I mean by 'one to one'. By that expression I mean that one imgage transforms into one RAW data set. Its not as though the transformation entails (say) a quadratic equation where the one image can give rise to either one of two RAW data sets. See http://www.yourdictionary.com/one-to-one You don't have a choice of RAW files for a given image. Nor do you have a choice of images for a given RAW file. But you have a choice of an infinite number of resulting images when the camera raw data is interpolated. None of them are exactly the same as your "source image" that was projected onto the sensor. .... and none of them are the image defined by the RAW data. Close, maybe, but not exact. If you understood that, then the above part that you objected to should have made sense. If not, tell me what you think it all is and I'll try to explain the significance in a way that is directed at your response (rather than at the OP for this thread). JPEGs, TIFFs and RAW files all contain data required to create an image. A JPEG or TIFF contains the data for a single image. A RAW file contains information for something approaching an infinite number of images. The principal difference is that the format of JPEGs and TIFFs are independent of of the camera which created them while RAW files are not. The JPEG and TIFF images are no more, or less, independent of the camera than the RAW data. Eric Stevens |
#10
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Could you actually see photos made from RAW files?
Eric Stevens wrote:
On Sun, 31 May 2009 03:10:56 -0800, (Floyd L. Davidson) wrote: When are you going to mark your deletions. You still haven't figured out how it works, have you. What do you think I meant by 'statisticsl error limitations'? You meant to imply that using big words with no meaning will make it sound like you understand something you don't. But anyone who does understand the process can see that you don't. Yet you claim it is possible to create an image from data that isn't there! I have never said any such thing, and see no point in you making up distortions rather than discussion the topic at hand. You said the "source image" is what is projected on the sensor. Interpolation of course is the method by which the sensor data is converted to an image format for viewing. That's part of what I meant when I wrote of "the rules inherent in the camera's software". And you haven't yet figure out that one is the input to while the other is an output from. It is quite possible to change the raw data to effect while balance, but it isn't normally done that way (Nikon, for example, has hinted that they might be doing exactly that in hardware). ... and therefore it is a different image. But nevertheless there is only the one image which can be created from a set of unmodified raw data. But clearly that is not true. The raw data set does not define one single image. It can be interpolated to produce an image. But the interpolation can be done in a nearly infinite number of ways, each of which produces a *different* image. No one way is the _right_ way, they are all just as correct as the next. What is changed is the interpolation of the data when creating an image format. The raw data is not changed, and the raw file stays exactly the same. The way the data is manipulated during interpolation changes. An interpolated data set is a new data set. The interpolation does not produce a new raw data set. It produces an unique image. But only the one JPEG can be created from the RAW data providing the rules of the transformation do not change. There is no one set of correct "rules of the transformation". False. Every different raw converter design uses a different set of "rules". Coffin's dcraw.c uses one set, Nikon uses another, and several other raw converters are different from both of those. But they are working on the camera's saved RAW file, not the relationship between what the sensor sees and the saved RAW file. Exactly. So why are you claiming otherwise? The raw data set is not changed. But there are multiple, correct, different sets of rules used to generate an exact image from the raw data. The sensor locations are hardly irrelevant either. As I said, at least *nine* of them are used to generate each pixel in the resulting image, and you can be assured the location is relevant! It isn't one pixel and then 8 other randomly chosen locations... it's a group of 9 (or more). So? So please cease this silliness where you claim the sensor locations are irrelevant. The signals generated by the sensors are determined by the rules inherent in the camera's software. They are determined by rules inherent in the camera's hardware. The sensor is not manipulated by software other than clearing it and reading it. A given amount of light on one sensor locations produces *exactly* the same output from the sensor regardless of the camera's software. I should have said "The signals generated by the sensors are -interpreted- by the rules inherent in the camera's software". To that extent they are 'determined'. I quoted you exactly above. Now you want to change what you said. Regardless, you are still wrong. The signals from the sensor are interpreted according to *hardware* and the resulting data set is written to a RAW file format. That is what is "interpreted" by software. As I have already said, there is a one to one correspondence between the source image and the RAW file. You can say that all you like, but it still requires at least *nine* different sensor locations to generate data for each pixel of the resulting image. It is not a one to one relationship. I see the problem. You misunderstand what I mean by 'one to one'. By that expression I mean that one imgage transforms into one RAW data set. Its not as though the transformation entails (say) a quadratic equation where the one image can give rise to either one of two RAW data sets. See http://www.yourdictionary.com/one-to-one So you now admit that it is not software at all, but a hard wired hardware transform. By next weekend we may force you into writing something that is clear enough to make some sense. You don't have a choice of RAW files for a given image. Nor do you have a choice of images for a given RAW file. But you have a choice of an infinite number of resulting images when the camera raw data is interpolated. None of them are exactly the same as your "source image" that was projected onto the sensor. ... and none of them are the image defined by the RAW data. Close, maybe, but not exact. That is precisely what I've been trying to get through your head! Good. Now you can get on with a sane discusssion of raw data processing. The raw data does not define one specific image. When the data is interpolated there is then an image! -- Floyd L. Davidson http://www.apaflo.com/floyd_davidson Ukpeagvik (Barrow, Alaska) |
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