Lens matching on Canon
I am currently having trouble with the recognition of a Sigma 150-500mm f/5-6.3 lens on Canon. This lens gives a lens ID of 174 and I recently submitted a patch (issue 921) to include this lens in the list embedded in canonmn.cpp. This works for some pictures and not others.
Eviv2 was changed recently to take the maximum aperture of a lens into account for some ID numbers and looking at those pictures where the lens is recognised correctly versus those where it is not what I believe is happening is that the lens reports the maximum aperture for the focal length it is currently set to whereas the code in canonmn.cpp assumes the lens will report the maximum aperture at any focal length. Thus depending on the focal length for that picture the maximum aperture value either matches or doesn't.
Any idea how to resolve this?
BTW I have reported this as a separate issue because I suspect it will affect more than just this lens, i.e. any case where a variable aperture zoom appears in an ID conflict.
Updated by Niels Kristian Bech Jensen about 8 years ago
- Category set to metadata
- Assignee set to Niels Kristian Bech Jensen
- Target version set to 0.25
Would it be possible for you to attach some test images to this report? I would like some images where the lens is detected correctly and some where it is not detected. Small JPEGs with full EXIF data are fine.
Niels Kristian Bech Jensen
Updated by Steve Fosdick about 8 years ago
- File 20131014_163513_1136.jpg 20131014_163513_1136.jpg added
- File 20131014_163522_1137.jpg 20131014_163522_1137.jpg added
- File 20131014_163556_1142.jpg 20131014_163556_1142.jpg added
Here are some pictures going through the zoom range. There are more pictures in the set but here I have included one picture for each distinct maximum aperture reported by the lens and only the one where the maximum aperture is reported as F5 works correctly.