EXIF - Get width and height of the embeded thumbnails

[RainerG]

How can i get the witdh und height of the embeded thumbnails from my DNGs?

[Mario]

The thumbnail is usually 160 or 256 pixel on the long edge.
This information is buried in a IFD (usually IFD0) and should show up in the Metadata Panel when you switch to the Browser mode. Search for width and take your pick.

[RainerG]

I think I expressed myself wrong.
(ich glaube, ich habe mich falsch ausgedrückt)

I mean the preview in the DNG file. If i show my DNGs (Canon 760D 6000x4000) in the explorer (i have fast picture viewer installed) and i have reduced the pix in LR or ACR then they shows me for example 4500x3000 Pixel (the correct pixel). IMatch shows me alway 6000x4000.

[Mario]

I don't understand.

IMatch shows the pixel size delivered to it by the image library (via WIC codec) when it ingested the file. This is not the size of the embedded preview, but the size of the DNG file.

[RainerG]

I don't understand.

IMatch shows the pixel size delivered to it by the image library (via WIC codec) when it ingested the file. This is not the size of the embedded preview, but the size of the DNG file.

Ich schreib das jetzt mal in deutsch (und jage es dann durch den Google-Übersetzer).

Ich suche nach einer Möglichkeit die Abmessungen der in den DNGs eingebetteten Vorschaubilder abzufragen.

Ich speichere meine DNGs über ACR mit großem Vorschaubild, also den tatsächlichen Abmessungen, die das (ggf. auch beschnittene) Foto hat. Einige Zeit lang war diese Einstellung aber auf Mittlere Größe. Also statt z. B. 3666x2444 (Original DNG = 6000x4000) hat das Vorschaubild im DNG 1024x683 Pixel. Da das Vorschaubild beim Export (und Umwandlung in JPG) in IMatch genutzt wird, bekomme ich dummerweise auch nur 1024x683 Pixel dabei heraus.


Same Text with GOOGLE-Translator:

I write that in German (and then chase it through the Google translator).

I'm looking for a way to query the dimensions of the thumbnails embedded in the DNGs.

I save my DNGs via ACR with large preview image, so the actual dimensions, which has the (possibly trimmed) photo. For some time, however, this setting was on medium size. So instead of z. B. 3666x2444 (Original DNG = 6000x4000) has the preview image in the DNG 1024x683 pixels. Since the preview image is used during export (and conversion to JPG) in IMatch, I stupidly get out only 1024x683 pixels.

So I'm trying to identify the images that have the thumbnail in mid-size.

Conveniently, with the dimensions of the preview image, I would have (if all the embedded preview images are stored in large size) the trimmed dimension. All of the DNGs (ex CR2) in IMatch, whether trimmed or not, have the original dimensions (eg 6000x4000) via the parameter Image width / Image height.

The preview view of IMatch (ie via ENTER key) knows the dimensions of the preview image (which is probably also displayed in the view). These are displayed at the bottom of the file name.

Ich versuche also die Bilder zu identifizieren, die das Vorschaubild in Mittlerer Größe haben.

Mit den Abmessungen des Vorschaubildes hätte ich praktischerweise dann (wenn alle eingebetteten Vorschau-Bilder in groß gespeichert sind), die beschnittene Abmessung. Alle DNGs (ex CR2) haben in IMatch, egal ob beschnitten oder nicht, die Originalabmessung (also z. B . 6000x4000) per Parameter Bildbreite/Bildhöhe.

Die Previewansicht von IMatch (also per EINGABE-Taste) kennt die Abmessungen des Vorschaubildes (das ja auch wohl in der Ansicht angezeigt wird). Diese werden unten neben dem Dateinamen angezeigt.

[Mario]

Run the "List Metadata" Preset in the ExifTool Command Processor.
Search for Width. Depending on the DNG version, the application producing the DNG, the version of that application etc. you should find three entries for width. One for the thumbnail (IFD0), one for the full-size RAW (SubIFD usually) and one of the preview (SubIFD1 or so).

Use that info to setup a filter or a data-driven category in IMatch to find the files with small previews.
NOTE: If IMatch does not show these tags in the Browser mode of the Metadata Panel, it has not imported these tags (These are superfluous tags usually not interesting for humans). You can enable the import of these tags in the Tag Manager and then do a forced reload of the metadata of your files.