EXIF data inconsistent from the same camera?

[JLGF1]

In the attached, iMatch shows the EXIF data from my Canon G9X.  I was surprised to see that the EXIF is not consistent even though all shots taken from the same camera.

Is that uncommon for the EXIF data to end up that way?  Or just a fluke with the camera's EXIF output?  I know that EXIF data can be hit or miss, but I assumed it would be consistent coming out of the same camera ie all right or all wrong.  As you can see, most of the pics ended up in the "unknown" category with the rest divided among the other two (note the lens range)

Note: I grayed out a different camera lens in the snippet just to avoid any confusion.  There is one Canon model and one Lumix model (grayed out).

Thanks for any insight.

[pajaro]

In the attached, iMatch shows the EXIF data from my Canon G9X.  I was surprised to see that the EXIF is not consistent even though all shots taken from the same camera.

Is that uncommon for the EXIF data to end up that way?  Or just a fluke with the camera's EXIF output?  I know that EXIF data can be hit or miss, but I assumed it would be consistent coming out of the same camera ie all right or all wrong.  As you can see, most of the pics ended up in the "unknown" category with the rest divided among the other two (note the lens range)

Note: I grayed out a different camera lens in the snippet just to avoid any confusion.  There is one Canon model and one Lumix model (grayed out).

Thanks for any insight.

Are these unknows straight out of the camera files (raws, jpgs), or are they post-processed jpgs? It frequently happens to me that some PP programs remove some metadata (e.g. ON1 RAW).

[Mario]

There is no standard for lens names. Most camera vendors are unable or unwilling to write a proper lens name (as on the lens itself) into the EXIF data. Some camera vendors even encrypt lens data to make it harder.

Basically the lens is encoded into several EXIF fields. The "lens id" field is a mess. Camera vendors use the same number for different lenses, 3rd party vendors (Tamron, Sigma) reuse lens ids used by camera vendors or their own. The same is true for the other tags which are designated to carry lens information.

ExifTool tries to make the best of it. Phil maintains huge tables in ExifTool which map lens data, maker and model to specific lens "names". A camera metadata record may end up with four to six lens name records, each more or less useful. IMatch builds on that and maps this hierarchy of lens names to a common standard "Lens" tag. For that it uses 8 potential input fields, in a special sequence, taking the best match.

If your screen shot shows the default "Lens" data-driven categroy shipped with IMatch, it is created from this virtual lens tag (photools.com::IMatch\2900\lens\0).
If ExifTool fills different lens fields (other firmware version, files processed in other application, camera recorded different info) the contents of this tag may differ, even for the same camera body. That's rare but I have seen worse things in metadata.

You can improve this category for your specific environment.

Look at the metadata contained in your files (Metadata Panel, switch to Browser Mode) and look for a metadata tag that describes the lens better, or more consistently.
Then change the default Lens category to use this tag instead of the composite tag IMatch creates.

If this does not help, you can use the "replace" feature in the data driven category to "fold" different lens names into one common name. For example, replace the "10.2..." with "Canon 10.2.." to make both lens names end up in the same category.

I would guess that for the incomplete lens name, some data in the EXIF record is missing that allows ExifTool to produce a better lens name. Maybe this file was processed in another application which stripped some or all of the maker notes when writing the image. Then crucial data is missing and you will end up with issues like this.

[ubacher]

You can also look at the metadata directly by using the exiftool: F9-E.
Select List all metadata

You can create your own listing of only the fields you want - a bit cumbersome though but easier for comparison.
(If the metadata is in a xmp file you need to specify this!)

[JLGF1]

Should I be able to batch-correct this with an IMatch meta-data template?

[Mario]

Should I be able to batch-correct this with an IMatch meta-data template?

No. Lenses are identified via several metadata tags, and most of them are treated as read-only. You would have to put the right bits into the right places, depending on the camera model. I'm not sure if this is possible (ExifTool handles several tags as read-only) but maybe Phil Harvey can come up with an idea.

First you should figure out what the problem is and why different lenses are identified in your files. There must be surely some differences in metadata.

[JLGF1]

> There must be surely some differences in metadata.

I expect so, but then I'm thinking about the best way to correct it, if possible, with the least amount of effort.

The first theory that I need to investigate is whether any P-P affected the EXIF data. I know that most of my tools supposedly don't alter the EXIF, but TBD.

But, the stats seem reversed:

ie the vast majority (95%+) show up in the "unknown" category.  And only 4-8 pics in the more precisely recognized categories.  Of course, this camera is non-ILC so there can only be one lens involved.

Those numbers are opposite of what I would expect if due to P-P as I know I haven't edited 95% of the images.

I will dig further into the meta-data as soon as I have a chance.

Thanks.

[Mario]

You can use the ExifTool Command Processor (Tool menu) to see the RAW metadata in your files. This avoids any potential re-mapping etc. performed by ExifTool IMatch when importing and mapping the raw metadata. Press <F1> when the ECP tool is open to get usage info.

Use the List Metadata preset for a start, and then use the search box on the bottom right to search for lens. This should yield all relevant lens data in the file.