Export to camera roll reduces file size

[defaultuyciz18otv16]

I shoot large DNG raw files on a Leica Q2, import them to Lightroom on my iPad via an SD card reader USB-C adapter, edit them, then export them as the highest quality JPGs possible, at 100%.  The images are smaller in size when exported to camera roll or shared to a shared album, and are larger when "exported as" and then saved to files.  I would like to have the images at maximum size be able to be saved directly to camera roll, not just files.   I conducted several tests using the identical source DNG image from Lightroom.  When I choose "export as" and select 100%, sRBG, and save to files, the image is 20mb.  When I choose "export as" and select 100%, sRBG, and save to shared album, the image is 7mb.  When I choose "export as" and select 100%, sRBG, and "save image" (presumably meaning saving to camera roll), the image is 7mb.  When I choose "export to camera roll" the image is 7mb.  When I choose "share to" and select "add to shared album" the image is 7mb.  When I choose "export to" and select "add to shared album" the image is 7mb.

My goal is to export from Lightroom to camera roll at maximum file size and resoluton and then store

my final output from a shoot in an album that I can then share with friends and family, either by sharing the album or via texting the images themselves directly.

Currently, to accomplish this goal, I have to "export as" to files, then save from files to camera roll.  That is the only way to avoid reducing the file size from 20gb to 7gb, per the above example. 

any ideas if Adobe is aware of this issue and planning to fix it?

[JohanElzenga]

The real question is: does this need to be fixed? If you save an image as JPEG, then the file size does not necessarily reflect the image quality. It's logical to think that 20 MB must give a better quality image than 7 MB, but did you ever try to see the difference? Read this to get an idea. It's not tested with Lightroom but Lightroom Classic, but the results should be the same.

[defaultuyciz18otv16]

Excellent article, and excellent point.  Yes, the images look different.  The difference is slight but noticeable.  The larger file size has less noise and is sharper.  Regardless, though, shouldn't a "100%" export mean the same thing no matter what destination is chosen?  Particularly if different sizes go to Files vs Camera Roll.  That doesn't make any sense at all.

[JohanElzenga]

The Camera Roll is a special image storage place that is managed by Apple Photos. Perhaps that has something to do with it.

[defaultuyciz18otv16]

I thought that too, but I am able to save to Files at 20mb, then from Files I can save to Camera Roll, and in the Camera Roll the images are 20mb.  Based on that, Lightroom should be able to save at 20mb in Camera Roll.  Agree?

[Jim Wilde]

I've tried to do what you are doing, and in all cases I get the same size each time, no matter what the destination is. 

[defaultuyciz18otv16]

That is fascinating.  Are you starting from a DNG file or a different format?

[Jim Wilde]

I've done it with a CR3 from my Canon R5, and with a DNG which was created in LrC from a CR3. I've exported to Files, to the Camera Roll and via Airdrop to my Mac desktop. Same size everytime (which is what I'd expect if the export settings are the same each time).

Have you rechecked with another file, making absolutely sure that the export settings are identical?

[defaultuyciz18otv16]

I'll do another test with a few different files.  Good suggestion.

[Jao vdL]

Just tried this on my iPhone and my iPad starting from a dng file that is available at full resolution in the cloud and the file ends up exactly the same size in Files as in Photos when using the same settings (I chose 100% sRGB jpeg) in the app. Not sure why this wouldn't work like that for you. Perhaps on the first try, the full resolution image didn't download yet and you were working from a smart preview?

[defaultuyciz18otv16]

I have conducted a new test of two different DNG files, exported at the same time.  The results are the same as above:

When I select "export to camera roll," the export is 6 or 7MB.

When I select "export to files," the result is 6 or 7 MB.

When I select "export as" and then select "save to files," the result is 20MB.

(There is no option to "export as" and then "save to camera roll").

This makes me think that the "export as" uses 100%, but the regular "save to camera roll" or "save to files" option uses a smaller percentage.

[Jim Wilde]

All those different export types (Export As, Share to, Export to Camera Roll, Export to Files) have their own settings menu, so please make sure you have checked them all when doing export size comparisons and make sure they are all set to 100% (or the same percentage if using less than 100%).

[defaultuyciz18otv16]

I see the settings menu for "Export As" but I don't see a settings menu for "Export to Camera Roll".  Perhaps that's it.  Apologies for the ask but where is that settings menu?

[Jim Wilde · Accepted solution]

Tap the icon to the right of the export option:

[defaultuyciz18otv16]

That did the trick.  I feel like an idiot.  Thank you very much everybody for your help!