System Information
Operating system: Windows-10-10.0.18362 64 Bits
Graphics card: GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 430.86

Blender Version
Broken: version: 2.80 (sub 75), branch: master, commit date: 2019-07-29 14:47, hash: rBf6cb5f54494e
Worked: (optional)

Short description of error
The camera depth of field always treat 1 Blender unit as 1 meter regardless of the scale setting.

Exact steps for others to reproduce the error
Set unit system to metric and scale to 0.01, now 1 unit should be 1 cm, the cube is 2 cm, the camera is about 10 cm away, but the depth of field remain the same even though it should produce more blur.