P: Include Subject Distance Metadata

[Jeff A. Goulden]

I'm sure this has been discussed before but I was not able to find any previous posts.  Since the Fall of 2013 Lightroom no longer captures the subject distance into the Lightroom metadata.  I remember hearing that subject distance was not considered to be accurate data and that's why it was dropped.  I reviewed a bunch of my older images and subject distance seems reasonably accurate to me.  I'd like to know who and why the decision was made to drop this data.  And what it would take to once again start capturing it upon import.  If the camera records data, it should be captured by Lightroom during import.

[GoldingD]

Your fellow members in this community are not Adobe. And we have no inside info.

Oh, some might have researched on this, perhaps using google. but not likely as the issue at hand is so much of no concern to perhaps all but a few.

Note that LrC does not show much metadata, lots of data not shown. Note also, that it does not alter that unshown metadata. Well perhaps unless striped on user purpose during export (and not all)

Incidentally, not all cameras fill that bit of metadata in.

[johnrellis]

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Subject Distance was removed from the Metadata panel in LR 3.4.1. But it was always available via custom metadata tagsets (which you could make manually or with the Metadata-Viewer Preset Editor plugin).  LR 11 added back the ability to display Subject Distance via the Customize button:

My test catalog includes 95 different cameras from 15 different manufacturers, and only five record EXIF Subject Distance:

[Jeff A. Goulden]

My custom metadata panel includes subject distance.  However, it only displays the distance on image taken prior to 2013.  Is Lightroom Classic once again capturing subject distance?  I still don't see it displayed for images taken after 2013?

[johnrellis]

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"My custom metadata panel includes subject distance.  However, it only displays the distance on image taken prior to 2013.  Is Lightroom Classic once again capturing subject distance?  I still don't see it displayed for images taken after 2013?"

As I described in my previous reply here, the issue is that newer cameras aren't recording the field EXIF:SubjectDistance.  I just checked my test catalog, and it now has photos from 115 different camera models, 110 of which haven't recorded SubjectDistance:

I haven't done an exhaustive investigation, but It appears some cameras from some manufacturers are recording values in the non-standard proprietary MakerNotes metadata section, in fields variously named FocusDistance, FocusDistanceLower, FocusDistanceUpper, ManualFocusDistance, MinFocusDistance.  LR's Metadata panel doesn't display any non-standard proprietary fields.

[Jeff A. Goulden]

John, thanks for the response.



I use two cameras; Nikon D200 and Nikon D750. When I said that my pictures
before 2013 had subject distance and the pictures after that didn't I was
referring to the same Nikon D200. I don't think my D200 is causing the
problem. I use a custom metadata panel that I set up in Lightroom. It
includes subject distance. My D200 pictures taken before 2013 have subject
distance displayed in Lightroom. The D200 pictures taken after 2013 do not
have subject distance displayed.



I am assuming that my D750 captures subject distance but I don't know that
for sure. At any rate subject distance doesn't appear on my D750 pictures.

[johnrellis]

"When I said that my pictures before 2013 had subject distance and the pictures after that didn't I was
referring to the same Nikon D200. I don't think my D200 is causing the problem. I use a custom metadata panel that I set up in Lightroom. It includes subject distance. My D200 pictures taken before 2013 have subject distance displayed in Lightroom."

I only have four sample D200 photos (one from 2007?), and none of them contain EXIF:SubjectDistance.

You can see if the later photos contain the field EXIF:SubjectDistance using the Any Filter plugin's Filter command, as shown in the screenshots above.

Alternatively, upload one of those later photos to Dropbox, Google Drive, or similar and post the sharing link here, and I'll take a look at it.

[Jeff A. Goulden]

John, here's a screenshot of two files.  The one on the left was taken in 2011 and shows a subject distance of infinity in my custom metadata panel.  The one on the right was taken in 2022 and doesn't show a focus distance.  I'm not sure of what I am seeing in AnyFilter

[johnrellis]

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That indicates the camera has recorded in MakerNotes:FocusDistance (a non-standard, Nikon-proprietary field) 3.76 m in one photo and 7.94 m in the other:

Change MakerNotes:FocusDistance to EXIF:SubjectDistance and post a screenshot of that.

[Jeff A. Goulden]

John, it looks like EXIF:SubjectDistance doesn't return a value.  I'm not sure of the accuracy of MakerNotes:FocusDistance.  I don't think the bird in the picture was 7.94 meters (26 feet) away from me.  It was more like 15 feet away.

[johnrellis]

"It looks like EXIF:SubjectDistance doesn't return a value."

The Metadata panel displays what's in EXIF:SubjectDistance, so if that's not present, LR won't display anything. I'm not sure why older photos from the D200 would have that field but newer ones not -- perhaps a firmware update at some point?  

"I'm not sure of the accuracy of MakerNotes:FocusDistance.  I don't think the bird in the picture was 7.94 meters (26 feet) away from me.  It was more like 15 feet away."

I think the focus distance measured by the cameras is often inaccurate, which is why Adobe removed it from the Metadata panel way back in LR 3.4.1.   But I'm not expert in that issue...

[Jeff A. Goulden]

John, it looks like extracting Exif:SubjectDistance returned "no value" for both the older picture as well as the newer one.  And yet when I display using my custom metadata panel, the older picture returned Subject Distance : infinity.  That seems strange.  I think my custom metadata panel uses "com.adobe.subjectDistance".  Is that the same as Exif:SubjectDistance.

I think I will run the same test on a file that has a real subject distance rather than infinity.

[Jeff A. Goulden]

John, Okay here's a test using an older picture with a definite distance of 3.16 meters.  I really don't think anything changed on the D200.  I think that the Lightroom import process changed sometime in 2011 with a new release.  The data provided by MakerNotes:FocusDistance looks reasonable.  Is there any way I can access that data to display in my metadata panel?

[johnrellis]

"Okay here's a test using an older picture with a definite distance of 3.16 meters."

That's very curious. The photo appears not to have the field EXIF:SubjectDistance and yet LR is displaying a value for it.

Could you please upload that photo and new sample photo that doesn't display Subject Distance to Dropbox, Google Drive, or similar and post the sharing link here (or send it to me in a private message)?  I'd like to determine precisely what's going on.

[johnrellis]

"I think my custom metadata panel uses "com.adobe.subjectDistance".  Is that the same as Exif:SubjectDistance."

Yes.

"Is there any way I can access that data to display in my metadata panel?"

No, the Metadata panel won't display any of the proprietary fields in MakerNotes.  You'll have to use Any Filter (good for filtering and searching many photos at once) or the Metadata Viewer plugin to display all the metadata fields in one photo at a time.  Both plugins use the authoritative Exiftool utility to access fields within the photo file.

[Jeff A. Goulden]

John, thank you so much for your help.  I uploaded those same two raw files to Dropbox and I emailed you the link.

[Jeff A. Goulden]

Thanks John, I guess I'll have to use Any Filter if I need to do a deep dive into a photo or photos.  It would have been so convenient to have that data displayed on my metadata panel.  We'll have to blame Adobe for taking that feature away from us.

[drtonyb]

I have looked into this a bit.

Recently, Adobe made the Subject Distance and Focus Distance metadata available in the Custom metatdata panel, but just enabling it doesn't display the information for all images in the catalog. For my Nikon D50/D80/D90/D750, some of the images in my catalog have values in Subject Distance, while others have values in Focus Distance. Most have nothing in either field. The raw files have values in the Maker:FocusDistance field, but Exif:SubjectDistanceRange is always Unknown. Newly imported images get the Focus Distance field filled, not the Subject Distance. There seems to be some point where Adobe assumes the distance is focussed at infinity, even though there is a value in the Maker:FocusDistance field. There is also a Maker:FocusPosition field and I think this comes into play somehow too.

Doing some tests, I found the Maker:FocusDistance for an image shot with my Nikon AF-S 70-200mm lens @200mm had a value of 56.22m, yet taking a shot focussed on the same subject with my Nikon AF-S 24-70mm lens @34mm had a value of 5.01m. In LrC, the first image's Focus Distance was infinity, while the second image's Focus Distance was 5.01m.

It's all a bit strange and ultimately, totally unreliable and meaningless.

[Jeff A. Goulden]

Thanks for looking into this.  It is all very confusing and the end result is that I'm probably not going to get what I want or need in my custom metadata panel.  I included Subject Distance but it only shows for older files.  Thanks anyway.  I appreciate it.

[johnrellis]

"It's all a bit strange and ultimately, totally unreliable and meaningless."

Yeah, I don't understand the technical issues of why cameras don't or can't record the focus distance reasonably reliably.  Physically, it seems each focus position of a lens in a given camera body corresponds to an easily calculated distance.  

"There seems to be some point where Adobe assumes the distance is focussed at infinity, even though there is a value in the Maker:FocusDistance field."

I think this occurs when the camera has written infinity into the EXIF:SubjectDistance field. I'm fairly confident that LR is just displaying whatever is in that field.

[drtonyb]

"I think this occurs when the camera has written infinity into the EXIF:SubjectDistance field. I'm fairly confident that LR is just displaying whatever is in that field."

John, I think that you will find that Nikon does not have EXIF:SubjectDistance in its files, so LrC can't be using it.

I have examined my catalog and in the Helper databases there is a table that has extracted metadata from LrC images. Two columns in that table are com_adobe_SubjectDistance and com_adobe_approximateFocusDistance. Out of 10.5k images shot over that past 18 years, only 4 original NEF files have values in both columns and they were taken in 2009.

For the first three images, the values in the distance columns match the Maker:FocusDistance as reported by exiftool, but the fourth image does not. LrC has set infinity for this image, whereas the Maker:FocusDistance is 7.94 m.

Here are three shots taken within a minute of each other using the same camera and lens and includes the first image in the list above, yet their LrC Focus Distance and Subject Distance values are very different.

Exiftool reports Maker:FocusDistance for each one as 5.96 m, 14.96 m and 10.59 m respectively. The Maker:FocusPosition for these are 0x99, 0x0f and 0xdd. I'm almost convinced that any image with Maker:FocusPosition 0x0f is set by LrC to infinity regardless of the value in Maker:FocusDistance. The last image, DSC_412.NEF, in the list above also has a Maker:FocusPosition of 0x0f.

[johnrellis]

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I added more Nikon pics to my test catalog, and it now has 42 different Nikon models:

But of those, just 3 models, from 2009 and earlier, have recorded EXIF:SubjectDistance:

And 26 models, many of them recent, record MakerNotes:FocusDistance:

Of the 432 photos, only 4 have infinity stored in the LR Subject Distance field:

And for all 4, EXIF:SubjectDistance is also infinity. For these photos, MakerNotes:FocusPosition is some small value that isn't 0x0f.

It appears that MakerNotes:FocusPosition represents a lens-specific focus setting, whose interpretation is specific to the lens:

(FocusPosition is in decimal here.) The Z series only sometimes records MakerNotes:FocusPosition:

All the other models record FocusPosition whenever they record FocusDistance.

This spreadsheet has all the data and was generated by the Any Filter plugin's Sort command:

https://www.dropbox.com/s/77f3zd0b03xar2h/nikon-subject-distance.2023.01.02.csv?dl=0 

[johnrellis]

The LR Focus Distance field, available via the Customize button in the Metadata panel, is very curious.

It was added to LR 11, and it appears to sometimes display MakerNotes:FocusDistance.  I believe it's the only Metadata panel field that displays a MakerNotes field.  It's not accessible via the plugin SDK nor in smart collections or in library filters.

However, the Focus Distance field is often blank even though the photo contains MakerNotes:FocusDistance.  Of the various camera models in my test catalog that have MakerNotes:FocusDistance, these show blank Focus Distance:

- The Nikon Z series.

- Several models of Leica.

- Several models of Olympus, except the E-M5 and E-M5 III.

- The OM Digital Solutions OM-1.

Only the non-Z Nikons appear to map MakerNotes:FocusDistance to Focus Distance consistently.  (Other camera makes use differently named fields in MakerNotes to record focus distance, and I haven't tested them.)

[johnrellis]

Forgot to mention: Jeff sent me two sample photos from his Nikon D200, one that displayed Subject Distance in his LR's Metadata panel and one that didn't. Neither contained EXIF:SubjectDistance, and neither displayed Subject Distance in my LR 12.1.

It could be that some earlier versions of LR tried to import MakerNotes:FocusDistance into the catalog's Subject Distance, while later versions gave that up.

[johnrellis]

Jeff confirms that when he reimports the two sample photos into his LR 12 catalog, neither displays Subject Distance in the Metadata panel, while previously one showed it and the other didn't. He's pretty sure that photos taken with the same camera (D200) on 10/7/13 or earlier had Subject Distance and photos taken after didn't.  

I've tested LR 4.0 (released on 3/5/12) and LR 5.7.1 (12/13/14) and neither reads Subject Distance from those photos.  So most likely one or more LR releases between 4.0 and 5.7.1 were reading MakerNotes:FocusDistance into the catalog Subject Distance.

[Jeff A. Goulden]

The oldest picture I have that has Subject Distance was from December 23, 2009.  I have a picture I took on December 8, 2009 that does not have Subject Distance.  Both pictures were taken with my Nikon D200 and an 18-200 lens.  I must have upgraded Lightroom between those dates.  All pictures going forward from December 23, 2009 had Subject Distance until after October 7, 2013 when I must have upgraded Lightroom again.  It's a shame that Adobe quit supporting Subject Distance after initially supporting it.  I found it a somewhat useful data field.