LR 13 panorama file size

Report · Oct 13, 2023

As I understand, Lightroom version 13 now saves panoramas in new lossy DNG format (vs lossless DNG in LR 12.5 and older). This format should provide better compression than previous versions.

Here are the results of one of my tests. The panorama made in the previous version of LR is 429M. In the 13th version of LR it is 124M. However, if you try to convert the 429M file to lossy DNG format in LR 12.5 version you get 80M file. If same conversion is done in LR version 13, the file weighs 37.6M. That is, if we make a panorama in the past version of LR (e.g. 12.5), and then convert it to lossy DNG using the old or new version of LR, in any case the file size is noticeably smaller than when stitching the panorama in the new version of LR.

Is it a bug or a feature? )

Report · Oct 21, 2023

That's a really interesting question and I would also love to get an answer.

Report · Oct 21, 2023

I think you are comparing apples and oranges. AFAIK, the old panorama and HDR DNG files were also lossy compressed (but not the same compression), so you are kind of 'stacking two compressions on top of each other' this way, leading to more losses.

https://community.adobe.com/t5/lightroom-classic-discussions/p-regarding-jxl-compression-in-derived-...

-- Johan W. Elzenga

Report · Nov 06, 2023

I can't agree with you!

In LR v12.x I created a panorama of 4 frames. The source files in DNG (lossless) format was 166M. And the final panorama was 333M. It is unlikely that lossy compression was used here.
If I create the same panorama in new LR, the size of the final file will be 39M.

In past versions of LR I made panoramas and then exported them as lossy DNGs, and the space saving was up to 10 times or more. This means that earlier versions of LR than 13th used the losless version of DNG to save the panoramas.

Next. If I export the same 333M panorama as lossy DNG v.15.3, the file size is 11.6M. And if I export it as DNG v.14.0 - 30.8M.
If the 333M panorama was already lossy compressed, it would hardly be able to be compressed to 30.8M again with the same compression method.