How to Change Raw Files Imported as .dng to .DNG?

[Platographer]

For some reason, rather than just naming raw files imported as DNG with .DNG extension, LR Classic gives a choice as to whether to use .DNG or .dng. Unfortunately, I didn't realize that and so all of my imported photos are .dng. How do I tell LR Classic to change the already imported raw files to .DNG? It should be easy for LR Classic to do so since it is just changing the case of the extension, but I can't figure out how. Thanks.

[john beardsworth]

LrC doesn't allow you to do this. You would have to do it outside LrC, for example using Adobe Bridge (which is free and useful in its own right).

Assuming you have done some work on the dngs in LrC:

1. Select the files in grid view
2. Ctrl S to save work back to the files
3. In Bridge, select the files and use Tools > Batch Rename
4. In its New Filenames section, choose current filename, Name and Original Case
5. Start a new line and choose current filename, Extension and Upper Case - notice the Preview section in my screenshot
   
6. Remove them from Lightroom UPDATE, MY ERROR
7. In Lightroom, synchronize the folder and reimport the files

Do this on a small folder, and folder by folder until you have the idea. This method will preserve almost all of your LrC work - though not VCs, assignment to Collections.

[Platographer]

I have not made any adjustments on any of the files yet. This is a new catalog. I imported and assigned them to collections. I don't want to lose that work. Is it really necessary to reimport after doing the batch change in Bridge? What reason would LR have not to accept the .DNG files as identical to the ones it gave the .dng extension to? I'm mystified that Adobe would provide the option between .dng and .DNG on import thereby creating this issue with no way to change the case afterward. That is such an odd decision by Adobe to not allow changing the case after importing without going through a circuitous process. 

[john beardsworth]

Is it really necessary to reimport after doing the batch change in Bridge? . 

By @Platographer

If you don't do this, the files will have DNG extensions in Finder/Explorer but in LrC you will see them as dng.

As I said before, try it on a small folder to see if you like the results. But in general I'd just advise you to leave things as they are, and accept a few photos in the catalogue will be dng and others DNG.

[Platographer]

So if I batch change the extensions to .DNG in Bridge without doing anything else, it will not affect anything in LR? My catalog structure will remain intact and LR will act exactly the same as if I kept the extensions as .dng? 

Is there any benefit of setting the extension of future imports to .DNG? I would rather have consistency than some .dng and others .DNG. What downside besides how the extension appears does having .dng extension instead of .DNG extension have?

[john beardsworth]

So if I batch change the extensions to .DNG in Bridge without doing anything else, it will not affect anything in LR? My catalog structure will remain intact and LR will act exactly the same as if I kept the extensions as .dng? 

By @Platographer

Correct.

Is there any benefit of setting the extension of future imports to .DNG? I would rather have consistency than some .dng and others .DNG. What downside besides how the extension appears does having .dng extension instead of .DNG extension have?

By @Platographer

The benefit would be easing your own discomfort at having some .dng and others .DNG . I certainly share that, but I don't get too worried if some files get into my main catalogue with upper case extensions (I prefer the less shouty lower case). Maybe some are still in the catalogue, but I'll usually fix them immediately if I've nothing better to do, but there's no practical benefit. LrC's Library Filter and Smart Collections don't distinguish between upper and lower case, though some other apps do or can do. 

I said immediately because exporting an upper case DNG or sending it to PS would lead to upper case JPEG/TIF/PSD, so the discomfort grows! Also I backup the files as soon as I've decided to keep them, and I don't want a DNG on backup and a dng in Explorer/Finder/LR - just in case of I don't know what.

You said you've "assigned them to collections. I don't want to lose that work." I assume you mean collections in the technical way, ie in the Collections panel. It's for you to decide how much work you'd lose, but you could mitigate that by using other metadata that would survive removal from the catalogue and reimporting. Colour labels? Keywords? etc.