aperture size = area/radius/diameter?

[Gijs]

The aperture size, is that the diameter of the aperture or radius or area?

[PeloEV1]

the aperture size, the f number in photo?
f = aperture size
F = focale lenght (millimeter)
D = aperture diameter (mm)

f = F/D

Greater is the real aperture, lower is the f number.
Greater is the focal lenght, greater is the f number.

Hope this help you.

[Gijs]

I know about the relation between aperture size, focal length and f-stop, but I need to know if the aperture size in the camera dialog represents the diameter.

The help fize says the aperture is in world units, but still then it can be anything.

[PeloEV1]

For me, it's just a effect multiplier.
It seem to work the same manner as the parameter sample radius in the 3ds camera rollout...