[Digikam-users] PowerShot S100 RAW pictures not treated properly

Sun Mar 18 16:18:58 GMT 2012

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-Noëlle Augendre <mnaugendre at gmail.com
> wrote:

> Hi Jeremy,
>
> Did you make some progress on that issue?
>
> Thanks,
> Marie-Noëlle
>
>
> 2012/3/8 Jeremy D Rogers <jdrogers at 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-Noëlle Augendre <
>> mnaugendre at 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-Noëlle
>>>
>>>
>>>
>>> 2012/3/8 JD Rogers <rogersjd at 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
>>>>
>>>>
>>>>
>>>>
>>>
>>> --
>>> <http://www.marie-noelle-augendre.com/photos/>
>>>
>>> Mes dernières photos sont dans ma galerie<http://www.marie-noelle-augendre.com/photos/>
>>> .
>>> Retrouvez-moi aussi sur mon blog <http://www.mnaugendre.com/>.
>>> Et parcourez les Cévennes à ma façon avec Cévennes Plurielles<http://www.cevennes-plurielles.com/>,
>>>
>>>
>>>
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>>>
>>
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>
>
> --
> <http://www.marie-noelle-augendre.com/photos/>
>
> Mes dernières photos sont dans ma galerie<http://www.marie-noelle-augendre.com/photos/>
> .
> Retrouvez-moi aussi sur mon blog <http://www.mnaugendre.com/>.
> Et parcourez les Cévennes à ma façon avec Cévennes Plurielles<http://www.cevennes-plurielles.com/>,
>
>
>
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