Circle DoF Can't Find Focal Length Variable

Upgraded to 4.8.0, and checked out some of the new features, more specifically, the new Circle DoF (patch notes)
Problem is, I can’t seem to find the Focal Length variable, I can find 1/Fstop and Focal Distance but not Focal Length.
The only other thing with the word focal in the DoF options is Focal Region, but that doesn’t seem to do anything.
On top of that, it’s grainy as hell compared to the other two options, to those who used the preview, is that normal and how would I improve that?
Also, I don’t know if it matters, but I edited the DoF settings in the GlobalProstProcessVolume objects in the Minimal_Default map and StarterMap to check it out, I also added a camera and changed the settings there, still grainy and no Focal Length.

There is no Focal Length variable under DOF. I believe circle DOF uses the focal length of the camera to calculate the blur. If you want more or less blur then adjust the F Stop number. Lower numbers have more blur, higher numbers have less blur. Common aperture F Stops on camera lenses are 1.2 (aperture wide open), 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22 (aperture closed almost shut).

Oh ok, thank you, already kinda figured about the F Stop from just messing about with it.

Hmmm…I am also trying to use this, but it feels super weird. If I just use the fstop value…nothing changes at all. The only way to see that something happens is by adjusting the focal distance to something around 100 and then everything is just a blurry mess. I would really love to get to know how to use this properly.


The settings you want to have ticked on under Depth of Field are: Method - CircleDoF, Aparture F-stop (value=somewhat you would use for on a camera lens), Focal Distance (Normally this would be: Distance from camera to object in focus (with approx 1/3 focus in front and 2/3 focus behind). In Unreal its distance to object start in focus - something that makes it quite different result). Not sure if any of the other settings do anything in circledof method.

Use a object and a place where you can see all types of ranges - like in the Sun Temple.
Setup several camera path that are almost the same, but with different FoV and distances.

a screen shot please:)