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03-01-2015, 08:41 AM   #1
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Q7 DNG files being loaded at 1920x1280 vs. actual size - why?

I am discovering that DNG files from a Q7 are sometimes loaded as 1920x1280 resolution files. Capture One is an example. I posted about this in Capture One's user forum:

Phase One and Leaf-Mamiya Official User to User Forum • View topic - Bug: Losing 50% of my image area upon import

Capture One ignores the embedded JPG preview and builds its own from the data. Where could it possibly be getting the 1920x1280 resolution from? Does the Q7 incorrectly write "1920x1280" somewhere in the DNG file? Can this be fixed with a simple Python script?

03-01-2015, 08:59 AM   #2
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Very strange. Can you upload the RAW somewhere so we can have a look?
03-01-2015, 09:06 AM   #3
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QuoteOriginally posted by luftfluss Quote
Very strange. Can you upload the RAW somewhere so we can have a look?
Sure!

Here's a DNG file.

https://www.dropbox.com/s/yf3wildlmtifljw/IMGP0378.DNG?dl=0

It loads just fine in Aperture.

https://www.dropbox.com/s/g60pduaxu09fdz8/Aperture%20EXIF%20Data.jpg?dl=0

It gets cropped in Capture One.

https://www.dropbox.com/s/vj5ednxcemjg9q0/C1.jpg?dl=0

Some other RAW converters seem to report 1920x1280 resolution but use the embedded JPG preview for editing. Faststone seems to do this. Capture One builds its own preview from scratch. This is what was reported in the Capture One user forum.

Capture One has no problems reading the Q7 samples posted on Imaging Resources. The resolution is correctly reported. What could have changed in the latest Q7 builds that affects DNG information?
03-01-2015, 10:40 AM   #4
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Well, crap, it looks like I've used C1 trials on both my desktop and laptop. I remember trying it out on my desktop, but not the lappy. Meh.

I looked at your DNG... does the same problem present itself when taking pics in landscape mode?

03-01-2015, 11:07 AM - 1 Like   #5
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The value 1920 only appears in a single standard tag in the file, the width tag on the second subimage (which is a JPEG).

I made a program to walk TIFF files (DNG files are TIFF files) looking for values, just for you (well, most of it is the TIFF parser, which I already had). https://github.com/drougge/tiffwalk. This doesn't look in the maker notes or any other non-standard part of the file, but someone interested could extend it I suppose.

I'd say this is a bug in Capture One, it's mixing up subimages maybe (getting the raw data from the one marked as such, but assuming it's the last one and getting size from there, or something like that).

---------- Post added 2015-03-01 at 19:28 ----------

QuoteOriginally posted by 6BQ5 Quote
Can this be fixed with a simple Python script?
I don't know about the Q7, but the original Q uses your selected JPEG size for the preview images in RAWs, so setting that to full might let you work around the problem on any new images.

And you could replace the preview jpeg with something the right size on the other files. I have a program for that somewhere, but it doesn't seem to be on my github. I'll be right back to edit this post once I find it.

Well, it's part of something else, but here it is: https://github.com/drougge/exifstuff

Last edited by drougge; 03-01-2015 at 11:36 AM. Reason: +exifstuff
03-01-2015, 01:54 PM - 1 Like   #6
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QuoteOriginally posted by 6BQ5 Quote
I am discovering that DNG files from a Q7 are sometimes loaded as 1920x1280 resolution files. Capture One is an example. I posted about this in Capture One's user forum:

Phase One and Leaf-Mamiya Official User to User Forum • View topic - Bug: Losing 50% of my image area upon import

Capture One ignores the embedded JPG preview and builds its own from the data. Where could it possibly be getting the 1920x1280 resolution from? Does the Q7 incorrectly write "1920x1280" somewhere in the DNG file? Can this be fixed with a simple Python script?
LR5 imports it as a fully dimensioned image (3000x4000) showing a centered crop of 2664x4000 that can be further fine tuned in the Develop Module, as you wish. Perhaps Capture One has a bug that prevents it from reading the Q7's DNG properly?

Just sayin'... M
03-01-2015, 02:09 PM - 1 Like   #7
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EXIFtool (Full export attached as IMGP0378.txt)
QuoteQuote:
Subfile Type : Reduced-resolution image
Image Width : 1920
Image Height : 1280
Bits Per Sample : 8 8 8
Compression : JPEG
Photometric Interpretation : YCbCr
FASTSTONE preview uses the above setting for JPG preview but full size for the RAW (see attached images below)
LR5 shows Default Crop Size : 4000 2664
EXIFtool shows
QuoteQuote:
Subfile Type : Full-resolution Image
Image Width : 4064
Image Height : 3000
EXIFtool for the original Q shows
QuoteQuote:
Subfile Type : Reduced-resolution image
Image Width : 4000
Image Height : 2664
Bits Per Sample : 8 8 8
Compression : JPEG
Photometric Interpretation : YCbCr
So it's in the EXIF written by the Q7's firmware that the issue originates from the Reduced Resolution tag..
Attached Images
     
Attached Files
File Type: txt IMGP0378.txt (10.9 KB, 188 views)
03-01-2015, 05:45 PM   #8
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Wow! Guys, this is awesome! Thanks for digging into this! I never, ever could have done something like this by myself!

So the EXIF data contains two resolutions. One is for "Full-resolution image" and the other is for "Reduced-resolution image". Is there a way for me to edit the "Reduced-resolution image" values in the Q7's DNG files and change them to 4000x3000? I understand that I would lose my 3:2 aspect ratio but that's OK. I'll just re-crop the image in post processing.

03-01-2015, 06:44 PM   #9
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QuoteOriginally posted by 6BQ5 Quote
Is there a way for me to edit the "Reduced-resolution image" values in the Q7's DNG files and change them to 4000x3000? I understand that I would lose my 3:2 aspect ratio but that's OK. I'll just re-crop the image in post processing.
The rawjpeg program in my exifstuff will replace the largest jpeg image with one you specify. Since that happens to be the one you want to change the size of you can use the program as is to specify any jpeg with the resolution you want. (Or if you're comfortable with python you can of course modify it to just change the size, but the DNG file won't technically be valid if you do that. (But I suspect it will work in most software anyway.))
03-05-2015, 08:04 AM   #10
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With droggue's help, I can now load Q7 DNGs. I'd like to try loading a DNG taken with the 08 wide angle lens. Does anyone have a sample I can download?

Thanks!
03-10-2015, 09:00 AM   #11
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Fellow forum member blackcloudbrew posted a DNG file created by a Q7 with the 08 lens. (Thanks!!) I replaced the incorrectly sized preview with a blank 4000x3000 resolution JPG using drougge's python script. Capture One v8.1.1 was able to import the image without any strange cropping.

Happy joy!
04-05-2015, 01:07 PM   #12
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Phase One has updated Capture One and quietly corrected the auto-crop issue for Q7 DNG flles. Hooray!
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