Yes, yes it’s true the iPhone doesn’t have the capacity for shallow depth of field rendering in the way your DSLR or Mirrorless camera does unless of course, you go very close to your subject.
However, there are some differences between what you can expect in terms of depth of field rendering from iPhone DNG and JPEG versions. Here’s a short video that discusses the differences, it may cause you to do a little re-evaluation of the accepted wisdom.
If you want to know more you can always buy my “Ultimate iPhone DNG” eBook on the iBooks store.
https://itunes.apple.com/us/book/ultimate-iphone-dng/id1274334884?ls=1&mt=11
Check out the video here: