Igor,
Further to my last e-mail I have also found an issue logged at the exiv2
redmin site: http://dev.exiv2.org/issues/1128
The developer there also mistook the ASCII value which seems to be there in
the maker note verbatim with exiv2 knowing about the lens and being able to
map the ID. I have added the patch to the issue to try to get support for
this upstream but I don't seem to have the privilege to mark the issue as
no longer resolved. I hope updating it will trigger an e-mail to those who
have previously been involved in it but I can't be sure.
On 27 February 2016 at 14:25, Steven Fosdick <stevenfosd...@gmail.com>
wrote:
> Igor,
>
> For comparison here is the output with the Canon 70-200 which is
> definitely known to exiv2:
>
> $ exiv2 -pt 20160207_114150_7099.cr2 | grep -i lens
> Exif.CanonCs.LensType Short 1 Canon EF
> 70-200mm f/2.8L IS
> Exif.CanonCs.Lens Short 3 70.0 - 200.0 mm
> Exif.Canon.LensModel Ascii 74 EF70-200mm
> f/2.8L IS USM
> Exif.Photo.LensSpecification Rational 4 70/1 200/1 0/1
> 0/1
> Exif.Photo.LensModel Ascii 25 EF70-200mm
> f/2.8L IS USM
> Exif.Photo.LensSerialNumber Ascii 11 0000000000
>
> The difference is that exiv2 has mapped the Exif.CanonCs.LensType ID
> number into a lens name. I must admit I don't why exiv2 works that way,
> particularly given these IDs sometimes clash, i.e. more than one lens uses
> the same ID and then it is necessary for the library to look at other
> pieces of data too.
>
> Anyway, it is necessary to get exiv2 to be able to map the lens ID to a
> string. If you grab the source for exiv2 you could try the attached patch.
>
> Regards,
> Steve.
>
> On 26 February 2016 at 17:48, Igor Blanco <igor...@gmail.com> wrote:
>
>> Hi everyone,
>>
>> Not sure if this could be a bug or something related to my installation
>> so I decided to write here before just in cae.
>>
>> I have a "TAMRON SP 70-200mm F/2.8 Di VC USD" with Canon mount, I use it
>> on my Canon 6D.
>>
>> This lens was not part of lensfun so lens correction could not be applied
>> to it. So I send Torsten Bronger the requested Raw samples and he was
>> really kind to prepare the required lenscorrection profile.
>>
>> I suppose this correction profile will go into lensfun's next release but
>> I attach it here so that anyone with the same lens can test and use it now
>> by placing it in ~/.local/share/lensfun directory.
>>
>> If I enable lens correction module in darktable though the lens is not
>> correctly detected, I can choose the lens by hand and it works great but it
>> is not detected automatically. Instead a 255 appears where the lens model
>> should appear.
>>
>> Torsten told me that this is probably related to Exiv2 library so before
>> reporting to them I tried this command on my Ubuntu 14.04: exiv2 -pt
>> 20160117_0011.CR2|grep Lens
>>
>> And this was the output:
>>
>> Exif.CanonCs.LensType Short 1 255
>> Exif.CanonCs.Lens Short 3 70.0 - 200.0
>> mm
>> Exif.Canon.LensModel Ascii 74 TAMRON SP
>> 70-200mm F/2.8 Di VC USD A009UUD
>> Exif.Photo.LensSpecification Rational 4 70/1 200/1
>> 0/1 0/1
>> Exif.Photo.LensModel Ascii 40 TAMRON SP
>> 70-200mm F/2.8 Di VC USD A009
>> Exif.Photo.LensSerialNumber Ascii 11 0000000000
>>
>> So it seems to me that Exiv2 does indeed recognize the lens.
>>
>> I have shared a RAW in case someone can check if it also happens to them:
>> https://www.dropbox.com/s/55jh1w7mkoc3ox2/20160117_0060.CR2?dl=0
>>
>> Any clue? Should I report this as a darktable bug?
>>
>> Thanks
>> =============
>> Igor Blanco.
>>
>>
>>
>>
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>
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