[Digikam-users] Re: Tamron lens not properly recognized

[Remco Viëtor]

on Monday 23 May 2011, Gilles Caulier wrote: 
> 2011/5/23 Marie-Noëlle Augendre <mnaugendre at gmail.com>
> 
> > My new Tamron 70-300 mm F4–5,6 Di VC USD is identified as a Canon EF
> > 28-105 mm in Digikam!
> > I've looked at the same pictures in other programs:
> >  - UFRaw does the same (I guess it is "normal" as they both use the same
> > library?)
> >
> 
> Yes, Exiv2 library
> 
> 
> 
> >  - RawTherapee calls it a 70-300 mm but from Canon!
> > Focal length is OK.
> >
> > Is there a way to correct this? Or is it simply a matter for the next
> > upgrade, or so?
> >
> 
> Report this problem to Exiv2 bugzilla : http://www.exiv2.org
> 
> Gilles Caulier

Well, I see usually a list of possible lenses in the makernote section of the 
EXIF metadata (Sony A330).

This makes me suspect it's *not* an error in the Exiv2 library, but caused by 
duplicate identifiers provided by the lens manufacturers; i.e. the exact lens 
used is not registered as a string containing a description, but as an integer 
value, decided by the lens manufacturer (and they don't seem to be talking too 
much with one another). 

So the best you can hope for is that the authors of the Exiv2 library add the 
name of the (unidentified) lens you used to their lists. I'd suggest attaching 
a full description of your lens and a RAW image to the bug report, so they can 
extract the data and pick up the proper ID code.

The focal length seems to be encoded separately and independently of the lens 
ID (and at least for me, seems correct).

(to illustrate: I get 1 ID string for my Sony kit lens, 2 for my Tamron 90mm 
macro and 8 (yes, eight) for my 70-300 mm Sigma, and those last 8 don't 
include the exact model... All this in the makernote section of the EXIF 
metadata)

Remco