Why did they take out DoF Underwater?

Question is up there , answer is unknown , i like it underwater , it does a cool underwater distortion effect without crippling fps (as long as you dont set it too high) , so i brought it back in!
like always i will try to do an Option for it :) so you can decide if you want underwater blur or not

soooo.... it can look really different depending on if you login underwater and what your settings are at , here are 2 examples how it might look

an extreme but somehow more realistic one                                                        normal underwater with my new default settings