Quite a while ago now, back in 2012 I think, Adobe announced lossy DNG. Like many photographers I did not see the point but now that Adobe Lightroom Mobile has been released it makes more sense.
You see when you select a RAW file to sync from your desktop you don’t get the large RAW file synchronised across to your iPad, or a jpeg that with its 8 bit compression is easy to break when editing.
To quote Adobe
‘Lossy DNG allows something in-between Raw and JPEG in terms of size but retains the flexibility in terms of adjusting White Balance and preserving detail’
Its this lossy DNG file that gets transferred to your iPad and its that you are working on. In this scenario it makes a lot of sense.
With cameras regularly producing RAW files over 16 MP now even 24 MP now common and the top end cameras at 36 MP, it would be useful if camera manufactures started to use lossy DNG. When you want a file smaller then RAW but still with the ability to edit more flexibly then a jpg it makes sense.
I suspect some camera manufactures like Ricoh and Leica may adopt it but the Canon and Nikons of the world will either keep offering RAW/JPG or offer their own proprietary lossy RAW format.