Hi Willem!
If you choose to share both full size jpeg files, then the exif info
would be available to all.
What is your goal... for example, are you hoping to better the in-camera
jpeg export, or equal it?
What denoise edits did you perform in dt?
What are you thoughts on Halgeir's questions below?
Kind regards,
Ken
On 02/13/2013 02:53 AM, Halgeir Kjønås Rennehvammen wrote:
What is the exif data on the picture?
The one from Darktable have a lot of high iso noise, and the other from
Canon camera lacks detail.
I don't know your settings on the Canon camera but i suppose it's default?
Default your Canon camera always remove iso noise from pictures when
data from the camera sensor are saved as jpg.
You have writting nothing about your settings in Darktable, but if you
have not done this, try to switch on noise removal.
<...>
Why not you post your raw file so we can work with it and find the best
settings in Darktable?
Then you can see how to achieve near to or better than camera jpg results.
)-|algeir
Den 13. feb. 2013 07:52, skrev Willem Ferguson:
Dear dt colleagues,
I have run into similar problems in the past. I do wildlife photography,
often under impossible light conditions. I shoot in RAW + JPEG. The JPG
exported from dt sometimes differs markedly in resolution and detail
from that of the JPEG that the camera creates. I actually submitted
correspondence to this forum about it, but because of clumsiness on my
side in access to the images the message was never posted here. Here is
the unposted message and a link to demo photos. Compression ration is
definitely not the determining factor.
"I export many photographs to JPG as a format for sharing images with
others. My Canon camera is configured to save RAW as well as hi-res JPG
images. Images are 18 Mpixels RAW. Most of the time I manipulate the RAW
image, export the final product to JPG and then use the JPG in
communications with other people. Frequently, the JPG export from
Darktable is MUCH more grainy than the JPG that the camera saves at
shoot time. I use dt 1.1.1.2 on Ubuntu 12.10. If I edit the "native"
Canon JPG file with GIMP, there is very little graininess introduced. Is
there an explanation for the grainy exports from dt? "
Kind regards,
Willem Ferguson
Link to demo photos: Hope this works.
https://www.dropbox.com/sh/3n1gmle42s6p5cd/vV967SzKGO
Kind regards,
Willem Ferguson
On 12/02/2013 21:37,[email protected] wrote:
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Today's Topics:
1. Discrepancy Between Darkroom vs jpeg Export ? User Error or
Bug? (Ken March)
2. Re: Discrepancy Between Darkroom vs jpeg Export ? User Error
or Bug? (Salvador Laiz)
3. Re: Discrepancy Between Darkroom vs jpeg Export ? User Error
or Bug? (Ken March)
----------------------------------------------------------------------
Message: 1
Date: Tue, 12 Feb 2013 10:02:46 -0800
From: Ken March<[email protected]>
Subject: [Darktable-users] Discrepancy Between Darkroom vs jpeg Export
? User Error or Bug?
To:[email protected]
Message-ID:<[email protected]>
Content-Type: text/plain; charset="windows-1252"
Greetings!
Currently I'm editing 28 very noisy sports photos. They were all shot
outdoors under a heavy cloud cover, late in the afternoon near dusk, at
1600 ISO and a slow lens (F5.6 to F5.0) on a 15 mega-pixel camera,
(Canon 500D).
After I edited, and exported 4 of these photos to jpeg, I noticed
differences between the noise in the jpeg files versus what is seen in
darkroom.
I'm new to darktable, so I'm wondering if this might be user error!
For one of these files in question, I have a screen-shot of what
darkroom displays, as well as the jpeg, xmp file, and originating cr2
file available here,
https://www.dropbox.com/s/2wb2p3zzqokpnqg/denoise-differences.zip
(~22MB). (First time sharing via dropbox, so let me know if I've screwed
it up.)
For reference, the denoise tools that I've implemented are:
1. raw denoise ? threshold 0.01, blend mode unbounded, opacity 100%
2. demosaic ? amaze, edge threshold 0.003, color smoothing 2 times,
match greens full and local avg
3. denoise (non-local means) ? patch size 3, strength 100%, luma 50%,
chroma 100%, blend mode unbounded
4. sharpen ? radius 2, amount 0.5, threshold 0.5, blend mode off
The differences are subtle, but exist. In particular there are two
things I've noticed:
First,the noise seen in the pavement in the foreground and of the bumper
sides around the lower portion of the karts is smoother in darkroom (as
seen in the example screen-shot) than as seen in the jpeg. The zoom
level is 1.5:1, btw.
The second discrepancy is that in the jpeg there a couple of light dots
on the leading kart's bumper in the area in front of his rear wheel,
which are not seen in the darktable screen-shot.
Why is there a discrepancy between what is seen in darktable versus the
exported jpeg?
(I hope the answer is user error! :-) )
It will improve my work flow to understand this discrepancy.
Kind regards,
Ken
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