DOF controls

[Madman]

Maybe this has been covered somewhere else in the forum but I haven't been able to find it. Is there anyone (Jesse, probably  ) who can explain to me the difference between "max radius" and "object size" in the DOF calculation? Most of the time I achieve the result I like by trial and error, but it seems that the controls behave differently each time I use different formula parameters.

[Jesse]

I just can try to:
The "max radius" is of course the maximum blurring radius applied to the image in pixel width of the 1:1 scaled image.
So if you downscaled the image, you have to use larger sizes.

The "object size" parameter influences the radius along the Z distance, from the nearest part of the object to the
farest.  Might be not physically correct, but a viewpoint isnt it neither.

So a low object size value should tend to a more microscopic look, a bigger one should tend to a view of a larger object.
Especially when using a larger value the maximum radius could be only in the nearest distance, so you need larger
"max radius" values to archive some blurring.

[Madman]

Thanks for your quick response, Jesse. Your description of the function of "object size" was what I expected to find. However, when working with M3D, I find that higher values often have the same effect (i.e. a microscopic effect) as smaller values and that the maximum "size-effect" is reached with values close to 0.5. It is something I've experienced with several (combinations of) parameters, although all of them were hybrids. Am I doing something wrong?

[Jesse]

All i can say is that it surely does not depend on the fractal type, the DoF effect makes no assumption on that, just relays
on the Zbuffer values and the already calculated colors.
As said, higher values needs often greater radius values, and it depends on where the focus lies.
If the focus is not on very near parts, the blurring should more effects the nearer parts and left the farer parts as is.

But if 0.5 is ok for you, than go with it. 

[Madman]

Thanks again! I think i'll just have to fiddle with the settings until I get an intuitive feel for it... Tune the entropy a little