Canon Lens incorrectly identified as Sigma Lens

[sans-c]

Describe the bug

Canon EF100-400mm f/4.5-5.6L IS USM incorrectly identified as Sigma 100-400mm f/5-6.3 DG OS HSM in Exif.CanonCs.Lens field. Exif.Photo.LensModel shows the correct lens.

To Reproduce

Steps to reproduce the behavior:

1. consider this file:
   

which is an out-of-camera, otherwise unprocessed jpg

2. exiv2 -P kt file | grep Sigma
   results in: Exif.CanonCs.LensType Sigma 100-400mm f/5-6.3 DG OS HSM

Expected behavior

The lens used was a Canon EF100-400mm f/4.5-5.6L IS USM and should be detected as such.

Desktop (please complete the following information):

• OS and version: Linux (Endeavour)
• Exiv2 version and source: exiv2 0.28.2 from Arch repo

Additional context

The EF lens was mounted to an RF mount via a genuine Canon adapter. No idea if this has any influence. Unfortunately I cannot currently test this lens on an EF-mount.

[kmilos]

Can't reproduce w/ exiv2 0.28.2 on MSYS2 UCRT64 (nor CLANG64), I get different output that highlights there is aliasing:

$ exiv2 -Pkt -g LensType 307808061-44995e12-71e5-4a10-8cd1-0799d61f4cd4.jpg
Exif.CanonCs.LensType                         Canon EF 100-400mm f/4.5-5.6L IS USM *OR* Sigma 100-400mm f/5-6.3 DG OS HSM
Exif.CanonFi.RFLensType                       n/a

$ exiv2 -V
exiv2 0.28.2

Possibly related to or duplicate of #2746

[kmilos]

@sans-c Unrelated: would you mind asking the Arch exiv2 package maintainers to add the brotli dependency as well please? It seems it's enabled anyway (via curl?), just not listed explicitly...

[sans-c]

@sans-c Unrelated: would you mind asking the Arch exiv2 package maintainers to add the brotli dependency as well please? It seems it's enabled anyway (via curl?), just not listed explicitly...

Not sure what qualifies as a dependency and what doesn't. As you mentioned, curl is listed and curl itself depends on brotli. I don't have any affiliation with Arch, nor do I have any accounts there to contribute, but that can change of course. :) I'll see what I can do.

As for the issue: that's interesting. I stumbled across this by using darktable, as so many others. I skimmed through the issue you linked but didn't get much out of it for now. If you need any more input or someone to test stuff, feel free to ping me.

The EF lens was mounted to an RF mount via a genuine Canon adapter. No idea if this has any influence.

Can you speak to this perhaps? My gut feeling is, that mount adapters shouldn't have any influence but thats unsubstantiated. What is your take on this?

[kmilos]

Not sure what qualifies as a dependency and what doesn't. As you mentioned, curl is listed and curl itself depends on brotli.

These are independent features for exiv2 - one could build w/o curl support for disabling web access, but still want brotli for parsing compressed JPEG XL metadata. Hence it is best these are listed as separate, explicit dependencies/features. The fact that on Arch curl depends on brotli (i.e. is built w/ brotli support) is pure chance.

nor do I have any accounts there to contribute, but that can change of course. :) I'll see what I can do.

If you feel like it, it would be great, thanks. I don't use Arch, so I have even less of an incentive to register 😉

My gut feeling is, that mount adapters shouldn't have any influence but thats unsubstantiated.

It should not in this case. As I said, it works in my environment.

I think it's best the issue discussion continues in #2746, I'll close this (and your other issue) as a duplicate.

[kmilos]

I'll see what I can do.

@sans-c Never mind, I found the package maintainers' email and contacted them directly. Thanks anyway!

[sans-c]

@sans-c Never mind, I found the package maintainers' email and contacted them directly. Thanks anyway!

:D I just requested my account (which was granted) and was about to raise an issue since I wasn't sure if mailing directly would be frowned upon. Anyway, good to know. :)

[kmilos]

I wasn't sure if mailing directly would be frowned upon. Anyway, good to know. :)

I might ping you back still if there is no reply. Ta.

[kmilos]

@sans-c I never got a reply from the Arch maintainers, so please open an issue in their GitLab, TIA

[sans-c]

@sans-c I never got a reply from the Arch maintainers, so please open an issue in their GitLab, TIA

done :)

[kamiccolo]

@sans-c I never got a reply from the Arch maintainers, so please open an issue in their GitLab, TIA

done :)

the update got merged: https://gitlab.archlinux.org/archlinux/packaging/packages/exiv2/-/commit/1b9e30f5403194f81dd6bed9997b5bfc95da4dd0

;)

[kmilos]

Thank you both!