Panorama DNG size is enormous

Jerry C

• 2022年12月02日 18:32

When creating a panorama of 8 approximately 66MB images in single row, I would expect the final panorama image file to have the same pixel bit depth and be no more than 8 times the size of the original RAW files (less assuming the overlapping parts would be merged). Even if the entire image information was coded into the final DNG, the image file would be no more than 528MB. In fact it was 2.14GB, i.e. 4 times the size of the individual RAW files.

The panorama image dimension was 358MPx (28282 x 12615). Each of the 8 images dimensions were 45MPx (8192 x 5464), resulting in the same 358MPx. So the final image does not discard any one the overlap in merging to the final DNG panorama file.

Exporting as a TIF results in an image of 1.34GB. Exporting as 80% JPG results in an image of 17.9MB, which is not quite as good as the original. Exporting as a JPG with 300px/in at 100%, results in a JPG file of 245MB, which is almost indistinguishable from the DNG panorama file.

Why is the file size so large? Is the bit depth increased in the process of merging? If so is there a way to control this so the final DNG file is not so ginormous? 

Also, the DNG file can only be displayed by opening with C1, which implies that the DNG file contains additional information needed to display the panorama image than is in the total of that of the original individual raw files. 

Last, exporting a panorama in JPG or TIF works in C1 23, but while the export appears in the history in C1 22 (version 15.4.3.4) no file is actually exported and C1 22 will thereafter not export in any format until closed and reopened. On closing, C1 22 displays that it closed because of an error and offers to report it to Capture One.

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  Jerry C

  • 2022年12月03日 02:26

  I previously submitted a request regarding the error in C1 22 when exporting a panorama merge file, but have not heard back.

  I submitted a report regarding panorama DNG file size, today.

  I posted to the forum because I am curious about how other users observations about exporting panorama DNG images in C1 22 and file size in C1 22 and 23 (versions, above).

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  Jerry C

  • 2022年12月04日 05:19

  This is normal behavior, apparently. The DNG file is a demosaicized/debayered conversion with a couple more bits of depth than the original RAW file. No data is discarded from the stitched DNG file. This results in the 2.14MB file resulting from 8 stitched images from my Canon R5. The good news is the cop preview file is actually somewhat smaller than a singe one of the 8 RAW files, because the preview was trimmed when I cropped the panorama file to eliminate the black area due to use of perspective projection. So, the database is not affected by the size of the DNG file.

  You could store about 500 panoramas from R5 images per TB of storage. A GB here, a GB there, and pretty soon you're talking big storage (to paraphrase the quote incorrectly attributed to Everett Dickson). Fortunately, storage is getting cheaper. 

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  Phrank

  • 2022年12月05日 19:39

  Hi, I wasn't happy C1 is producing such big (not compressed) DNG files. I use C1’s panorama merge only for the smaller panoramas and merge them in 25% only with previews. If I need them bigger I render them again. Anyway, I was able to open these DNGs in Photoshop 2023 and Affinity Photo 2. An Option to render them in JPG or lossy DNG would be good. Or use a proxy/preview file with all the settings and render them in a big file only on export.

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