writing back to maker data on the m9

[jbl]

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Is it possible to write back to the Maker data on a DNG produced by an M9? I basically want to override the g-stop value. If I set Exif.FNumber using exiftool, Lightroom shows the correct data in the metadata display, but shows a “-“ under the histogram. I’m guessing one is pulling from the Maker data and another from the EXIF data.

 

Thanks,

 

-jbl

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[01af]

Is it possible to write back to the Maker Notes data on a DNG produced by an M9? I basically want to override the g-stop value.

Yes, sure. Phil Harvey's ExifTool can do that.

 

But don't think it's easy to mess around with the EXIF exposure data! You need not only to adjust the f-stop but (at least) also the brightness so the data will always match. And you'll need to understand the difference between aperture number and aperture value.

[jbl]

I did some digging... I have a file, that was taken with a Noctilux at f/0.95. The tags from exiftool seem to support this:

 

0x3406 ApproximateFNumber : 1.0

0x3408 ExternalSensorBrightnessValue : 1.04

0x3407 MeasuredLV : 3.60

 

Lightroom then decodes this as f/1.4 and writes that into the FNumber and ApertureValue tags:

 

0x9202 ApertureValue : 1.4

0x829d FNumber : 1.4

 

For some reason, running

 

exiftool -s -H -sort

 

dumps the ApertureValue as 1.4 instead of the APEX value of 0.970853978431944 which is what ExifChanger shows even though ExifChanger just wraps exiftool.

 

Any ideas?

 

-jbl