I setup a camera system where you can define the f-stops in world-units, and tried to get a nice shallow depth-of-field similar to my meatspace 50mm/1.4f lens. Turns out, it’s as difficult to get a good shot in-game as in real life!
Starting with unrealistic naive boxy bokeh:
Transforming into a more hexagonal-like bokeh. Looks more natural.
The shape was created by rendering 3 different types of bokeh (3 rhombi) and combining them. You can clearly see the 3 rhombi in the unblurred version:
Final (though not perfect):
* Hexagonal Blurspages (p15-26)