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To:digiKam - Home Manage your photographs as a professional with the power of open source From:JD Rogers Subject:Re: [Digikam-users] PowerShot S100 RAW pictures not treated properly Date:Sun, 18 Mar 2012 11:18:58 -0500
 

Hi Marie-Noelle,

Sorry for not getting back sooner.. turns out the first few weeks of having a baby is not filled with free time.

I did a quick try at creating a lens entry for the S100, but so far I am not able to get the digikam distortion correction to work. I get an error "cannot find all lens information.." I'll look into to it further, but if you want to try playing with it, here is what I have so far.
(Note: the numbers I calculated for the distortion could stand to be improved and I'll do a better set of images with finer focal ranges when I get the lensfun library to work at all.)

I added the following entries to /usr/share/lensfun/compact-canon.xml

<mount>
<name>canonS100</name>
<compat>Generic</compat>
</mount>

<camera>
<maker>Canon</maker>
<model>Canon PowerShot S100</model>
<model lang="en">Canon PowerShot S100</model>
<mount>canonS100</mount>
<cropfactor>4.6</cropfactor>
</camera>

<lens>
<maker>Canon</maker>
<model>Canon PowerShot S100 5.2 - 26.0 mm</model>
<mount>canonS100</mount>
<cropfactor>4.6</cropfactor>
<calibration>
<distortion model="ptlens" focal="5.2" a="-0.021" b="0" c="-0.097" />
<distortion model="ptlens" focal="8.31" a="-0.06" b="0" c="-0.0315" />
<distortion model="ptlens" focal="13.42" a="-0.002" b="0" c="-0.01" />
<distortion model="ptlens" focal="26.0" a="0" b="0" c="-0.002" />
</calibration>
</lens>

Best,
JDR

On Thu, Mar 15, 2012 at 3:31 PM, Marie-Nolle Augendre <mnaugendre@gmail.com> wrote:
Hi Jeremy,

Did you make some progress on that issue?

Thanks,
Marie-Nolle


2012/3/8 Jeremy D Rogers <jdrogers@northwestern.edu>
Aha! I was thinking of looking into distortion correction. The idea was interesting, but I had no immediate need so I never looking very deeply into this. The s100 may be a good excuse to tackle it. If nobody beats me to it, I may take a run at this over the weekend. Thanks for the link, Marie-Noelle.

On Thu, Mar 8, 2012 at 10:16 AM, Marie-Nolle Augendre <mnaugendre@gmail.com> wrote:
Regarding the white balance, you can find here a whole set of pictures taken with different white balances: http://www.marie-noelle-augendre.com/fichiers/Darktable/

I provided them for the Darktable team to solve the same problem. They managed to correct the white-balance (it is OK now in Darktable RC1 version) but the lens distorsion problem remains.
i just got this answer on the DT list:
"Darktable uses Lensfun for lens correction. Apparently lensfun has no correction data for the S100...
You can calibrate it yourself:
http://lensfun.berlios.de/lens-calibration/ "
but I don't think I'll be able to do that. I'd rather someone more tech than I am do it.

Marie-Nolle



2012/3/8 JD Rogers <rogersjd@gmail.com>
I think that raw view is correct. It is raw, afterall. I wasn't so sure about the magenta tint (when I first read your post, I was thinking there was a dcraw version problem) but that could just be the effect of the white balance. Looking at your photo, it doesn't seem any worse than my test images. The distortion is dramatic for the s100's lens. I was reading about it some before I bought the camera. My understanding is that the in-camera processor corrects the distortion for jpg (and hence for the raw thumbnail preview). But raw is raw. And its pretty dramatic! The camera even has several "creative settings" like fisheye, toy camera, and minature effect that apparently alter how much distortion is corrected.

I hadn't played with raw on this camera much yet, so you've inspired me to look at it more. The distortion depends heavily on the focal length (zoom) of the lens, so the question is weather the digikam distortion correction can be setup to handle it. I just tried the lens auto-correction in the batch queue manager using "meta data" and it failed, but I've never used that before, so I have to play with it more.

I guess the details of this lens must be entered into a lens library?

JDR





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Retrouvez-moi aussi sur mon blog.
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_______________________________________________
Digikam-users mailing list
Digikam-users@kde.org
https://mail.kde.org/mailman/listinfo/digikam-users




--


Mes dernires photos sont dans ma galerie.
Retrouvez-moi aussi sur mon blog.
Et parcourez les Cvennes ma faon avec Cvennes Plurielles,


_______________________________________________
Digikam-users mailing list
Digikam-users@kde.org
https://mail.kde.org/mailman/listinfo/digikam-users