No FocusDistance metadata for Z mount lenses?

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michaeladawson Forum Pro • Posts: 13,389
No FocusDistance metadata for Z mount lenses?
1

I had reason to review a large number of images for focus distance.  I opened up ExifToolGui (v5.16) using ExifTool v11.63 (latest version).

I examined photos taken with a Z7 and either the Nikkor 500mm f/5.6 PF (using FTZ adapter) or the Nikkor 24-70mm f/4 S.

All the photos taken with the adapted 500mm PF had a FocusDistance metadata value.  None of the native lens photos had any FocusDistance metadata property.  It wasn't that it was 0 or blank, there was no metadata property for FocusDistance.

Has this been discussed before?  It seems to be a lens property not a camera body property since a Z7 was used with both lenses.  Do the Z mount lenses really not report the focus distance in the Exif metadata?

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Mike Dawson

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Nikon Z7
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jch2103B Regular Member • Posts: 487
Re: No FocusDistance metadata for Z mount lenses?
2

So it seems. My FX lenses (85mm f/1.8G and 70-300 AF-P) report focus distance, but that particular tag (Nikon::LensData0800\11\FocusDistance\0) doesn't contain data for Z mount lenses (at least not my 24/70 f4 S). In general, metadata is a mess, in large part because manufacturers (not just Nikon!) hide a significant amount of data they think only they need. There's a possibility that Z lens focus data is recorded in proprietary maker notes that aren't (yet) 'cracked' by ExifTool.

Also, I'm not entirely sure how accurate the focus distance data are.

 jch2103B's gear list:jch2103B's gear list
Nikon 1 V3 Nikon Z6 Nikon 85mm F1.8G Nikon 1 Nikkor VR 6.7-13mm f/3.5-5.6 Nikon 1 Nikkor VR 70-300mm f/4.5-5.6 +4 more
OP michaeladawson Forum Pro • Posts: 13,389
Re: No FocusDistance metadata for Z mount lenses?

jch2103B wrote:

So it seems. My FX lenses (85mm f/1.8G and 70-300 AF-P) report focus distance, but that particular tag (Nikon::LensData0800\11\FocusDistance\0) doesn't contain data for Z mount lenses (at least not my 24/70 f4 S). In general, metadata is a mess, in large part because manufacturers (not just Nikon!) hide a significant amount of data they think only they need. There's a possibility that Z lens focus data is recorded in proprietary maker notes that aren't (yet) 'cracked' by ExifTool.

Also, I'm not entirely sure how accurate the focus distance data are.

Thanks.  I don't need absolutely accurate focus distance data.

What I was doing in this case was trying to determine which images out of 100 were shot at minimum focus distance.  Or, more specifically, which images might not be in proper focus because the correct focus distance was less than minimum, so I can delete them without having to open up each one and inspect focus.

Many of the images from the 500mm PF were reported as 2.99m.  I suspect these were probably taken with the subject at less than minimum focus distance.  While doing this I noticed that the native Z lens did not report distance.

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Mike Dawson

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jch2103B Regular Member • Posts: 487
Re: No FocusDistance metadata for Z mount lenses?
1

See https://sno.phy.queensu.ca/~phil/exiftool/TagNames/Nikon.html for ExifTool information on Nikon lenses, and https://sno.phy.queensu.ca/~phil/exiftool/TagNames/Nikon.html#LensData0800 for data recorded (for some lenses) by Z6 and Z7.

I posed a question about Z lens focus distance data on the ExifTool forum: http://u88.n24.queensu.ca/exiftool/forum/index.php/topic,10400.msg54803.html#msg54803

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olyflyer
olyflyer Forum Pro • Posts: 26,656
Re: No FocusDistance metadata for Z mount lenses?
1

I think it is a bug. It has been discussed but it is good to bring it up again and I think it should be fixed but I don't think it will be.

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Nikon Z7
OP michaeladawson Forum Pro • Posts: 13,389
Re: No FocusDistance metadata for Z mount lenses?

olyflyer wrote:

I think it is a bug. It has been discussed but it is good to bring it up again and I think it should be fixed but I don't think it will be.

You may be right.  In some ways I hope you're right.  Seems more chance of fixing a bug than adding it.  Fortunately, I don't actually require focus distance for what I'm doing.

It just seemed odd that it wasn't there.  I wondered if perhaps it wasn't there because of the fly-by-wire focusing system.

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Mike Dawson

 michaeladawson's gear list:michaeladawson's gear list
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jch2103B Regular Member • Posts: 487
Re: No FocusDistance metadata for Z mount lenses?

michaeladawson wrote:

olyflyer wrote:

I think it is a bug. It has been discussed but it is good to bring it up again and I think it should be fixed but I don't think it will be.

You may be right. In some ways I hope you're right. Seems more chance of fixing a bug than adding it. Fortunately, I don't actually require focus distance for what I'm doing.

It just seemed odd that it wasn't there. I wondered if perhaps it wasn't there because of the fly-by-wire focusing system.

It's not a bug so much as Nikon (like all camera manufacturers) hiding information proprietary maker notes. If you want to help resolve this, see http://u88.n24.queensu.ca/exiftool/forum/index.php/topic,10400.msg54806.html#msg54806.

 jch2103B's gear list:jch2103B's gear list
Nikon 1 V3 Nikon Z6 Nikon 85mm F1.8G Nikon 1 Nikkor VR 6.7-13mm f/3.5-5.6 Nikon 1 Nikkor VR 70-300mm f/4.5-5.6 +4 more
jch2103B Regular Member • Posts: 487
Re: No FocusDistance metadata for Z mount lenses?
4

Good news! I sent Phil Harvey a set of images with known focus distance; he's decoded the Nikon maker notes so focus distance for Z6/Z7 will be included in Exiftool 11.64: http://u88.n24.queensu.ca/exiftool/forum/index.php/topic,10400.msg54828.html#msg54828

 jch2103B's gear list:jch2103B's gear list
Nikon 1 V3 Nikon Z6 Nikon 85mm F1.8G Nikon 1 Nikkor VR 6.7-13mm f/3.5-5.6 Nikon 1 Nikkor VR 70-300mm f/4.5-5.6 +4 more
OP michaeladawson Forum Pro • Posts: 13,389
Re: No FocusDistance metadata for Z mount lenses?

jch2103B wrote:

Good news! I sent Phil Harvey a set of images with known focus distance; he's decoded the Nikon maker notes so focus distance for Z6/Z7 will be included in Exiftool 11.64: http://u88.n24.queensu.ca/exiftool/forum/index.php/topic,10400.msg54828.html#msg54828

BRAVO!!!

I can't thank you enough!  I wanted to do the same thing but there's always something else to do.  Thanks again.

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Mike Dawson

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Wim Vanmaele Junior Member • Posts: 36
Re: No FocusDistance metadata for Z mount lenses?

olyflyer wrote:

I think it is a bug. It has been discussed but it is good to bring it up again and I think it should be fixed but I don't think it will be.

In the exif, there is a part that is standardized ...  But, all stuff that is inserted into the "maker notes" is like it describes: Notes entered by the maker ..  So, any firm that creates a picture and inserts an exif, has to follow standardized items, but in the makernotes it can insert anything it wants ...
I once did a survey and found more than 500 different items in it.
Even Adobe inserts data like  'history', ... when you open, eventually modify some stuff in a picture and save that picture in LR or PS.

olyflyer
olyflyer Forum Pro • Posts: 26,656
Re: No FocusDistance metadata for Z mount lenses?

jch2103B wrote:

Good news! I sent Phil Harvey a set of images with known focus distance; he's decoded the Nikon maker notes so focus distance for Z6/Z7 will be included in Exiftool 11.64: http://u88.n24.queensu.ca/exiftool/forum/index.php/topic,10400.msg54828.html#msg54828

Nice. Thank you.

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Nikon Z7
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