Re: [Gimp-user] image sharpness

2008-03-30 Thread David Gowers
On Mon, Mar 31, 2008 at 1:49 AM, Sven Neumann <[EMAIL PROTECTED]> wrote:
> Hi,
>
>
>  On Sun, 2008-03-30 at 15:17 +0100, norman wrote:
>  > I forgot to say that the JPEG is sharper than the RAW conversion.
>
>  Most cameras do some sort of pre-processing which usually involves
>  sharpening the image. One of the main points of using raw images is that
>  no such pre-processing is done.

Actually, yes. Norman, i now recall that it's a fairly standard thing
for serious digital photography, to run the final result through
'unsharp mask'.

for example, here:
http://www.aim-dtp.net/aim/techniques/linear_raw/index.htm
unsharp mask is used (in Photoshop) with r= 5, a=500, t=0.
(I think a=500 in Photoshop terms is 0.5 in GIMP terms)

Hope that helps.
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Re: [Gimp-user] image sharpness

2008-03-30 Thread Sven Neumann
Hi,

On Sun, 2008-03-30 at 15:17 +0100, norman wrote:
> I forgot to say that the JPEG is sharper than the RAW conversion.

Most cameras do some sort of pre-processing which usually involves
sharpening the image. One of the main points of using raw images is that
no such pre-processing is done.


Sven


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Re: [Gimp-user] image sharpness

2008-03-30 Thread norman

> Could it be that your camera sharpened the JPEG quite aggressively and you 
> did 
> not sharpen the result of the RAW conversion?

That could very well be the reason. I had forgotten that there is
sharpening going in the camera with JPEG which, of course, does not
happen with RAW.

Norman


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Re: [Gimp-user] image sharpness

2008-03-30 Thread Alexander Rabtchevich
If it is a common case, not some particular image, the difference is 
obvious: in-camera image processing includes noise reduction (blurring) 
and sharpening. The resulting image look and feel is a result of 
combination of NR and sharpening, acting in contrary directions. If you 
use UFRaw for RAW conversion, it has noise reduction (disabled by 
defaults) and has no sharpening.

David Gowers wrote:
> Okay, in that case I have no idea what is happening there.
>
> On Mon, Mar 31, 2008 at 12:47 AM, norman<[EMAIL PROTECTED]>  wrote:
>
>> I forgot to say that the JPEG is sharper than the RAW conversion.
>>
>>
>>   Norman
>>
>>  

-- 
With respect
Alexander Rabtchevich

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Re: [Gimp-user] image sharpness

2008-03-30 Thread Christoph Bergemann
Could it be that your camera sharpened the JPEG quite aggressively and you did 
not sharpen the result of the RAW conversion?

Am Sonntag 30 März 2008 16:17:07 schrieb norman:
> I forgot to say that the JPEG is sharper than the RAW conversion.
>
> Norman
>
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Re: [Gimp-user] image sharpness

2008-03-30 Thread David Gowers
Okay, in that case I have no idea what is happening there.

On Mon, Mar 31, 2008 at 12:47 AM, norman <[EMAIL PROTECTED]> wrote:
> I forgot to say that the JPEG is sharper than the RAW conversion.
>
>
>
>  Norman
>
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Re: [Gimp-user] image sharpness

2008-03-30 Thread David Gowers
Hi norman,

It certainly is possible -- I assume your jpeg is the blurry one, and
both pictures were taken with a tripod so no chance of accidental blur
-- then it's a matter of what quality you have it set to - on my
camera it needs to be Fine or better.; For RAW, that kind of option is
irrelevant and meaningless, you always get exactly the pixels the
camera saw.

HTH

On Mon, Mar 31, 2008 at 12:38 AM, norman <[EMAIL PROTECTED]> wrote:
> Unless my eyes deceive me I can see quite a difference in sharpness
>  between an image saved by the camera as a JPEG and the same subject
>  converted from RAW taken at the same time. Perhaps someone could tell me
>  whether this is possible or are my eyes being deceived by some other
>  difference between the two images.
>
>  Norman
>
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Re: [Gimp-user] image sharpness

2008-03-30 Thread norman
I forgot to say that the JPEG is sharper than the RAW conversion.

Norman

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[Gimp-user] image sharpness

2008-03-30 Thread norman
Unless my eyes deceive me I can see quite a difference in sharpness
between an image saved by the camera as a JPEG and the same subject
converted from RAW taken at the same time. Perhaps someone could tell me
whether this is possible or are my eyes being deceived by some other
difference between the two images.

Norman

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