Need help getting detail from RAW files - RAW Shooting and Processing - CHDK Forum
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Need help getting detail from RAW files

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Offline Stevvie

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Need help getting detail from RAW files
« on: 15 / July / 2008, 15:16:37 »
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I've started using the RAW feature of CHDK and my Canon S5IS. I really love the colour results I'me getting but the RAW files lacks a fair bit of detail that the Camera Processed JPG images have. Here's an example, the UNCOMPRESSED DNG is on the Right and the JPG from the camera is on the Left. As you can see there seems to be much less detail in the DNG image than there is in the camera proccessed JPG file. Any suggestions would be helpful.
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Canon S5IS 1.01B
Canon A80
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Offline wontolla

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Re: Need help getting detail from RAW files
« Reply #1 on: 15 / July / 2008, 15:50:23 »
Remember that the JPG from the camera has been sharpened, unlike the DNG file.

If you apply some unsharp mask to the DNG you can get that level of detail. edit: something similar to the original JPG.

Don't forget that RAW post processing is not about getting "better results" (it's very difficult to beat the adoc fine-tuned processing done in-camera) but about getting "the results that you want".
« Last Edit: 16 / July / 2008, 06:36:01 by wontolla »
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Offline PS

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Re: Need help getting detail from RAW files
« Reply #2 on: 15 / July / 2008, 19:04:21 »
You can't get more detail (i.e. actual information) by sharpening. You will only get illusion and artifacts.
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Offline LjL

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Re: Need help getting detail from RAW files
« Reply #3 on: 15 / July / 2008, 19:25:37 »
No, as a matter of fact you can't create information that isn't in the shot to begin with, of course.

That doesn't mean sharpening is only "illusion and artifacts", quite the opposite.

If you know the point spread function of your lens, and apply the deconvolution that reverses that, you are guaranteed to obtain an image that's closer to the original subject - minus the noise.

If you don't know and can't measure the PSF, a wisely applied unsharp mask will get you similar results. No illusion in there.
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Offline carlos

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Re: Need help getting detail from RAW files
« Reply #4 on: 15 / July / 2008, 20:58:38 »
Quote from: LjL on 15 / July / 2008, 19:25:37
....... a wisely applied unsharp mask will get you similar results.

True, but first; necessary, skillful, noise reduction ... or noise will be sharpened.

It's a game of "beat the jpeg"!  (Win some, lose some.)

carlos
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Offline Aged

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Re: Need help getting detail from RAW files
« Reply #5 on: 16 / July / 2008, 03:46:19 »
Keep an eye on PerfectRAW. It offers various demosacing options but it is under development.
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Offline LjL

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Re: Need help getting detail from RAW files
« Reply #6 on: 16 / July / 2008, 08:34:57 »
Well, but software noise reduction does result in a loss of detail, unavoidably. It can give a more pleasant result, though, that's for sure.

Good sharpening, on the other hand, doesn't lose detail (aside from quantization), and it helps to bring the extant detail to the eye, as well as to provide a more faithful reconstruction of the original subject.

And, if it's JPEG we're talking about... we've lost a significant part of the detail already ;)
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Offline carlos

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Re: Need help getting detail from RAW files
« Reply #7 on: 16 / July / 2008, 11:55:42 »
Getting of topic aren't we?

I responded too quickly to the suggestion that sharpening should be used, with no mention of noise reduction, (RAW being inherently noisy).

OP Stevvie asked for suggestions re detail in  DNG example - there is considerably less detail, compared to the camera jpeg.

By the look of it, no amount of unsharp mask will bring the DNG conversion up to the camera image quality in this case. As  member PS points out; you may sharpen but you won't bring back missing detail.

So ... anybody ... any help for Stevvie?
 
WHERE'S THE DETAIL?

« Last Edit: 18 / July / 2008, 09:54:14 by carlos »
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Offline fudgey

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Re: Need help getting detail from RAW files
« Reply #8 on: 16 / July / 2008, 12:30:17 »
Well it's just not possible for a RAW file not to have all the detail the camera had when it started the process of filtering and encoding to a jpeg.

So, if those sample images up there are too far apart for a filter set similar to what the camera has to fix, the software which was used to display that DNG file as a 8-bit image for that jpeg up there (or, less likely, the software that was used to convert CRW to DNG) is responsible for the added loss of sharpness and needs to be replaced or set up properly.

No, I can't help there, I have no clue.
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Offline LjL

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Re: Need help getting detail from RAW files
« Reply #9 on: 16 / July / 2008, 13:51:01 »
The statement that the image on the right is the "uncompressed DNG" doesn't hold any water, and that's why there is no way to help Stevvie aside from telling what he's been told - to sharpen.

A DNG isn't 8bpp, while the image I see is. I doubt that the DNG would be 640x792; is the posted image a detail at 100%, or downsampled?
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