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10-02-2007, 07:11 AM   #16
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QuoteOriginally posted by ChrisA Quote
(snip) Which makes the answer to my question "yes, it has been demonstrated", but feel free to correct me if I've misunderstood it.

Huh? If I understand correctly, you asked whether anyone had "demonstrated a superior image obtainable from the RAW file, that was not available from the corresponding JPEG." Perhaps I'm missing something, but I don't see how Steve's images demonstrated that.

His images included an unmodified JPEG file, a heavily modified Silkypix file ("highlight recovery on at 4EV and exposure turned down 1/3EV"), and a heavily modified PhotoMatix file ("converted twice at different exposures (about -1EV and +1EV) and combined").

At the same time, he provided no evidence to show that Silkypix, PhotoMatix, or even a standard image editing program, could not do the same things (recover highlights, adjust exposure, combine images, etc) with that JPEG file, producing virtually identical results.

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10-02-2007, 07:36 AM   #17
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QuoteOriginally posted by stewart_photo Quote
Huh? If I understand correctly, you asked whether anyone had "demonstrated a superior image obtainable from the RAW file, that was not available from the corresponding JPEG." Perhaps I'm missing something, but I don't see how Steve's images demonstrated that.

His images included an unmodified JPEG file, a heavily modified Silkypix file ("highlight recovery on at 4EV and exposure turned down 1/3EV"), and a heavily modified PhotoMatix file ("converted twice at different exposures (about -1EV and +1EV) and combined").
I wasn't so concerned with the third one, but I thought that the second one was modified in Silkypix, starting with a RAW file, and that that result wasn't achievable with the JPEG. Admittedly that wasn't stated explicitly - maybe I was assuming too much.

If it came from the JPEG, then I agree, there's no evidence, but I don't see the point of that post at all, in that case. It's not all that interesting if it says no more than "here's the unmodified JPEG, but here's what you can do with it (in any number of clever ways)."
10-02-2007, 09:31 AM   #18
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I stand by what I said ChrisA. The wording of your post 'implied' some measure of mis-understanding vis-a-vis the viewing RAW images. Additionally, your reluctance to 'wade through' things has left you ill-prepared in significant ways. Added to your eagerness to 'jump to the next page' and you created much of the confusion and a large part of the antagonism and animosity of the thread.

Let's back-up and try again.

I'll assume that everybody knows that viewing a RAW file is nonsense--it's not a good assumption, but...

You should know that I'm not afraid of or reluctant to wading or for that matter swimming with all my ability through a sea of information.

A recent paper search netted exactly seven RAW-RGB conversion schemes in published literature. Three algorithms are held by mathematicians/ computer scientists as 'unique', differentiable from each other in significant non-overlapping ways. The other four are thought to be derivative or hybrids of these three unique methodologies.

One of these unique schemes is also readily adaptable to hard-coding as done for in-camera converters. This method has also been used in the software of at least one significant PC based converter. As far as the computer having more 'power' over the camera-this is insignificant to the algorithm proper except as to speed of delivery of the final product. The same math hence the same result are inevitable if both chip and software are properly coded.

The difference lies entirely in the input parameters. The camera has no keyboard so the trade-off for ease of operation was a small, discrete (easily numerable) input parameter set as apposed to the PC's much larger (still discrete) parameter set---plus/minus 3 or 5 -VS- plus/minus 256/1025 etc.

Given equivalent parameterizations there is no significant technical difference and only slight artistic difference between an in-camera JPEG as compared to a PC generated JPEG (when viewed on a suitable output device or medium). This has been demonstrated in a number of popular magazine and e-zines typically disguised as comparisons between external converters in Photoshop, Lightroom, RawShooter and others--others here including the in-camera conversion.

Now for where you jumped-ahead-a-page. There is significant adjustment from the default that is better utilized in the PC as opposed to in-camera--that's hardly a revelation. There is also significant adjust ability in a well prepared JPEG given sufficient retention of detail. This has also been demonstrated repeatedly.

It has yet to be shown (anywhere) that an absolute and completely definitive advantage is guaranteed to exist across all contingencies favoring RAW over JPEG--in fact it is not conclusive where such advantage might be found in a specific subject genre. The jump to labeling one as 'Pro' and one and 'amateur' is utter forum silliness.

Perhaps the thoughtful speculation on your part should be supplemented with some wading through available literature.


QuoteOriginally posted by ChrisA Quote
This is most certainly not the crux of the problem. I'd be surprised if you could find anyone taking part in the discussion who was unaware of this.


Yes, we know this.



And this.

The point is whether, if, as you say, you botch the settings, you can recover detail from the RAW file that cannot be recovered from the JPEG.

Another point that I haven't seen covered anywhere is the fact that the computer in your PC is a lot more powerful, with a lot more space to put program code, than the computer and memory respectively in the camera.

So all other things being equal, I'd hope that the computer could do a better job of the RAW - JPEG conversion than the camera.

So I don't think it's a given that a JPEG obtained by Silkypix or whatever, even at the default settings, will be the same as the JPEG generated by the camera.
10-02-2007, 10:25 AM   #19
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QuoteOriginally posted by jfdavis58 Quote
I stand by what I said ChrisA. The wording of your post 'implied' some measure of mis-understanding vis-a-vis the viewing RAW images. Additionally, your reluctance to 'wade through' things has left you ill-prepared in significant ways. Added to your eagerness to 'jump to the next page' and you created much of the confusion and a large part of the antagonism and animosity of the thread.
I wasn't aware of any antagonism or animosity on this thread. I didn't post at all on it until I asked this question:

QuoteOriginally posted by ChrisA Quote
Just out of curiosity (and forgive a certain reluctance to go through all those RAW vs JPEG threads ), has anyone published even a single photo taken in RAW+ mode (so that the two files really are the same photo), and demonstrated a superior image obtainable from the RAW file, that was not available from the corresponding JPEG?
.. to which Stewart_photo kindly pointed me at one of the earlier threads. He also pointed out that I may have misinterpreted a post from SteveB, which I thought was very helpful.

The reason I mentioned RAW+ mode was since on the K10D, it gives you both a camera-generated JPEG, and a RAW file; both files from a single exposure, thus preventing any differences that might be introduced (and which would thus invalidate any comparisons) by attempting to compare photos taken at different times.

I didn't actually mention viewing RAW files at all, so I'm not clear how I've implied any confusion.

However, be all that as it may....

QuoteQuote:
One of these unique schemes is also readily adaptable to hard-coding as done for in-camera converters. This method has also been used in the software of at least one significant PC based converter. As far as the computer having more 'power' over the camera-this is insignificant to the algorithm proper except as to speed of delivery of the final product. The same math hence the same result are inevitable if both chip and software are properly coded.
Fair enough. If that's what they've done in the camera, then as you say,

QuoteQuote:
The difference lies entirely in the input parameters. The camera has no keyboard so the trade-off for ease of operation was a small, discrete (easily numerable) input parameter set as apposed to the PC's much larger (still discrete) parameter set---plus/minus 3 or 5 -VS- plus/minus 256/1025 etc.
Now I'm interested in your comment here:

QuoteQuote:
It has yet to be shown (anywhere) that an absolute and completely definitive advantage is guaranteed to exist across all contingencies favoring RAW over JPEG--in fact it is not conclusive where such advantage might be found in a specific subject genre.
This goes some way towards answering my original question.

However, I am still interested in the specific contingency of a badly exposed photograph. Is there potentially more detail recoverable from the RAW file, than from the K10D-generated JPEG?

QuoteQuote:
Perhaps the thoughtful speculation on your part should be supplemented with some wading through available literature.
Perhaps so, but I was hoping one more knowledgeable than I would be able to condense an element of their knowledge for me, so that I don't have to become equivalently expert in order just to decide whether shooting RAW is worthwhile.

Please note, though, that at no time have I done any:

QuoteQuote:
labeling one as 'Pro' and one and 'amateur'
, which I agree with you would be
QuoteQuote:
utter forum silliness.


10-02-2007, 10:52 AM   #20
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QuoteOriginally posted by ChrisA Quote
I wasn't so concerned with the third one, but I thought that the second one was modified in Silkypix, starting with a RAW file, and that that result wasn't achievable with the JPEG. Admittedly that wasn't stated explicitly - maybe I was assuming too much.

If it came from the JPEG, then I agree, there's no evidence, but I don't see the point of that post at all, in that case. It's not all that interesting if it says no more than "here's the unmodified JPEG, but here's what you can do with it (in any number of clever ways)."

In quoting my previous message, you skillfully deleted my answer. Again, he provided no evidence to show that Silkypix, PhotoMatix, or even a standard image editing program, could not do the same things (recover highlights, adjust exposure, combine images, etc) with that JPEG file, producing virtually identical results.

Edit: Since I have no desire to get into yet another long-winded RAW versus JPEG debate, Chris, I'll end my participation in this discussion here. Feel free to use whichever you want and I'll do the same. Others can make the same choices for themselves. As such, advocacy for one or the other is not really needed (but appears to be exactly where this thread is heading anyway).

stewart

Last edited by stewart_photo; 10-02-2007 at 11:07 AM.
10-02-2007, 11:18 AM   #21
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QuoteOriginally posted by stewart_photo Quote
In quoting my previous message, you skillfully deleted my answer. Again, he provided no evidence to show that Silkypix, PhotoMatix, or even a standard image editing program, could not do the same things (recover highlights, adjust exposure, combine images, etc) with that JPEG file, producing virtually identical results.
Sorry - there was no skill involved, I promise you.

As I said, I had assumed, possibly wrongly, that the second picture of the three had come originally from a RAW file, which was why he cited it.

QuoteQuote:
[I]Edit: Since I have no desire to get into yet another long-winded RAW versus JPEG debate, Chris
I don't either. I've obviously given the wrong impression somehow. If that was by drawing a wrong conclusion from the SteveB post then my apologies.

But I have no axe to grind either way - I'm just trying to understand why so many seem to believe that RAW is at least potentially so superior.

I'm not advocating either over the other, just trying to learn whether the commonly held view that more detail is recoverable from RAW than from JPEG when the photo is badly exposed, is true or not.

I sure don't want to bother with something that takes five times the space if there's no clear advantage.
10-02-2007, 11:27 AM   #22
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In fact, just to partially requote the original SteveB post:

QuoteOriginally posted by SteveB Quote
This RAW shot was taken with just a tiny amount of the sky blowing out on the LCD flasher, I pushed the exposure as much as I could to try and make the deep shaded trees not disappear into black without losing the sky, the embedded jpg is shown first and the Silkypix conversion basically had highlight recovery on at 4EV and exposure turned down 1/3EV.
(my emphasis)

His reference to a RAW shot, an embedded JPG and a Silkypix conversion is what made me think that he had a JPG and a RAW from the same shot, and got a better result converting the RAW than the JPG.

It's not entirely clear - I wish he was around to confirm my interpretation either way.

But that's where I coming from, that's all. As I say, I have no axe to grind either way, just a desire to get better photographs.

10-02-2007, 02:41 PM   #23
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QuoteOriginally posted by ChrisA Quote
This is most certainly not the crux of the problem. I'd be surprised if you could find anyone taking part in the discussion who was unaware of this.
Well, I'm no expert on this (that's why I asked ) but ...

On my linux system (Debian 4.0) with UFRaw installed I can preview the RAW images in the filemanager and I can open then in a few image editors.

I don't know what exactly is happening but I don't think they are converted to JPEG on the fly when I open them ?

Before I had UFRaw installed the Gimp and other programs complained about them beeing TIFF files in an unsupported format (12 bit sampler or something like that).

but I get the general idea (most "normal" image editors don't support these files (even the gimp doesn't with UFRaw installed so you are correct that they need to be converted to JPEG or TIFF to be viewed by most people).
10-02-2007, 09:16 PM   #24
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There must be 10 threads about this, but since you asked...

I shoot only RAW with the K100D. A RAW image contains more information than a jpg, hence the larger file size. I believe you won't necessarily see the difference until you get to larger sizes, though.

However, all the adjustments you might make to the RAW data is made before you convert it to jpg or whatever, so there is no degradation of the image as can happen (they say) to jpgs.

And, I don't have to worry about white balance as I can change it, or any other shooting parameters except ISO setting, after the fact.

Plus, the minor tweaking gives me the impression I have a hobby beyond just capturing the image :-)

With the Canon I shoot only jpgs as that is my only option.
10-02-2007, 11:41 PM   #25
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QuoteOriginally posted by stewart_photo Quote
You seem to be suggesting here that JPEG is the finish product while RAW offers more - the ability to edit or adjust afterwards. Of course, as you know, both JPEG and RAW files can be adjusted afterwards. With any decent image editing program, every adjustment possible with RAW can be accomplished with JPEG images (white balance, contrast, saturation, etc). stewart
Of course it can. But at cost.
The whole "prove it" part is a bit... pointless.

RAW contains more image data to begin with. JPG, which comes out of the camera uses lossy compression (correct me please, if you know any digital camera that uses lossless compression). This means that image editor, as good as it is, has less data to work with JPG files than when working with RAW files. You may or may not see the difference in final result, depending on the subject and the complexity of processing needed.

Further, when you save edited JPG as JPG again, you now have reduced image data twice, whereas when saving tweaked RAW as JPG has had image data reduced just once. That, by definition, is difference in quality. Again, depending on the picture and the complexity of processing you may or may not see the difference. But technically, there is a difference, hence some may describe RAW as superior. The difference is disputable subjectively, but not technically.

Also, JPG from one camera may be inherently better (in regards to compression and loss of image data) than from other camera and the gain from RAW may be different for different brands/models.

Whether one needs that "extra" from RAW is down to personal taste and/or needs.
10-03-2007, 01:19 AM   #26
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QuoteOriginally posted by aabram Quote
RAW contains more image data to begin with. JPG, which comes out of the camera uses lossy compression (correct me please, if you know any digital camera that uses lossless compression). This means that image editor, as good as it is, has less data to work with JPG files than when working with RAW files. You may or may not see the difference in final result, depending on the subject and the complexity of processing needed.

Further, when you save edited JPG as JPG again, you now have reduced image data twice, whereas when saving tweaked RAW as JPG has had image data reduced just once. That, by definition, is difference in quality.
Well RAW is considered to be "Lossless" so all camera's that produce images in RAW format use a lossless "compression" ? but that's not your point I know.

Anyways, I exported one of the RAW images a fellow forum member provided me to test my linux software for compatibility (still waiting for the camera to arrive at the store where I bought it) to a TIFF file and the RAW was approx. 11MB as you probably know BUT the exported TIFF was 32 MB approx ??? but maybe that's because I did some post-processing that was added to the file ?

Also, now I starting to understand what a person I know was talking about a few years ago, he was/is a hobby photographer but has little to no understanding of computers and technology. He had bought a book on digital photography and he claimed that you had to store your JPEG files to CD (no DVD's back then) ASAP since EVERY time you opened them they would degrade.

He thought that every time you open them with a viewer which I found odd, but he misunderstood the statement in the book. the images is "degraded" every time you edit/open it in a program like photoshop and then save it again.

But ... when I save a JPEG with the Gimp I can set the quality manually (default is 80% so it can do some compression) but I would think that IF I set it to 100% it would just save the JPEG in the original compression it came in without loss of data ? or is that assumption incorrect ?
10-03-2007, 04:44 AM   #27
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QuoteOriginally posted by Cloudy Wizzard Quote
Anyways, I exported one of the RAW images a fellow forum member provided me to test my linux software for compatibility (still waiting for the camera to arrive at the store where I bought it) to a TIFF file and the RAW was approx. 11MB as you probably know BUT the exported TIFF was 32 MB approx ??? but maybe that's because I did some post-processing that was added to the file ?
Pentax PEF files use lossless compression, thus the smaller size. PEF files are similar to TIFF, that's why some software assumes they're TIFF files but fails to open them. TIFF can also be either compressed or not, in uncompressed form it is bound to be much bigger. Try saving with various compression methods (LZW or ZIP for exmple) and see if that makes a difference.

QuoteOriginally posted by Cloudy Wizzard Quote
He thought that every time you open them with a viewer which I found odd, but he misunderstood the statement in the book. the images is "degraded" every time you edit/open it in a program like photoshop and then save it again.
True, only saving affects the quality. After you save-reopen-save the same image for 4-5 times even the blindest will see ugly artifacts, smearing of colours and the lack of crispness.

QuoteOriginally posted by Cloudy Wizzard Quote
But ... when I save a JPEG with the Gimp I can set the quality manually (default is 80% so it can do some compression) but I would think that IF I set it to 100% it would just save the JPEG in the original compression it came in without loss of data ? or is that assumption incorrect ?
In general JPG uses ALWAYS compression. There are lossless JPG formats such as JPEG-LS, JPEG-2000, but if not stated otherwise in image editing software, the default is standard format, which is lossy. 100% quality settig gives you maximum image quality considering the JPG format, that is it gives you minimum quality loss. But there is a loss nevertheless. Though there are exeptions, for example it is possible to rotate image by 90 degrees (and thus by 180 and 270 also) and re-save it without loss, without actually altering image date but just rearranging data blocks inside JPG file.

Suppose the original image quality is 100% and maximum JPG quality is 99% (can't be 100% as it wouldn't be JPG). But within the editor it still makes sense to indicate 100%, but this doesn't mean 100% of original quality but rather 100% or maximum available quality. Which may happen to be 99% (or 95% or whatever) of original quality.

Suppose you get from camera JPG image where there is 99% of image data available. As soon as you save it with maximum settings (99% quality retained) you will have 99% of original 99%, which would make 98.01% or original quality. Saving yet again gives another decreas and so forth. If you use stronger compression (=more loss) then the quality will degrade much faster. Say if you save 90% first time you get 90% of original quality. Saving yet again with 90% gives you 81% of original quality. Saving third time gives you 72.0% of orginal quality and it's obvious downhill from there.

Of course these numbers are just illustrative and fairly arbitrary, I have no idea how to truthfully represent the JPG quality loss precentages, but it gives the rough idea. Also, the percentages or the scale you see in image editor save dialog may not actually tell you how much image data is retained or discarded, it may just be an arbitrary scale for inbuilt compression engine, which then applies it's own secret algorithms. So 50% compression doesn't equal 50% loss in image quality.

It all relates to RAW vs JPG because RAW gives you at minimum one less image quality decrease step compared to JPG. Perhaps it is just 1% which cannot be possibly distinguished without extreme pixel peeping and comparing but still. If cameras would put out TIFF instead of JPG then it would be different story. But with JPG there is really nothing to argue about.

It all boils down to "is it worth it?" And that is what people start arguing about. Which is kind of silly.
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