View Full Version : DOF! Nothing out of focus! How do I fix that?

03-16-2004, 07:17 PM
I finally found (in top view) the "ring" around the camera that is the Focal Length. I have that line right in the middle of a bunch of objects. I tried F-stop 9 and 2 (because I forget if the lens wide open or closed tightens the focal length.) But no matter because neither extreme gave me that short depth of field I was looking for.

I seem to remember some kind of interface that described more precisely the actual DOF.

Anyway can someone please tell me what I am doing wrong here? My manual is in another country so I can't refer to it right now.


03-16-2004, 07:34 PM
Try a realy low f-stop, like .6 or something. I usually find I need really small numbers to get a narrow dof.

03-16-2004, 09:02 PM
I'm trying fstop of .2 and still everything is sharp as a razor. What gives? Should the focal distance be somewhere other than in the center of the objects?
The new help manual isn't helping with this one.

03-16-2004, 10:11 PM
This may be a dumb question, but are you sure your anti-aliasing is set high enough for DOF to kick in?

03-16-2004, 10:52 PM

The depth of field interface won't even activate unless AA is set to a least medium. My guess is that your object is too big to show depth of field. Depth of field becomes more apparent the closer the camera is to an object. So if your object is large and the camera is a few meters away from it, depth of field may not be apparent.

Like a real camera, a larger F-stop number closes the aperture which increases the depth of field (everything's in focus.) A small F-stop opens the aperture, decreasing the depth of field (only a portion of the scene is in focus).

How big is your object and what is your depth of field set to numerically? My guess is that if you moved your camera to within 100mm of your object and focused it on the leading edge you'd see depth of field effects.

For instance, in the attached comparison the top render shows a bracelet at its original 1x size (around 70mm in diameter). With the focal length set to 115 mm (focused on the spherical terminals) and an F-Stop of 4.0, you can easily see the effects of the depth of field. (Rendered Enhanced High, and the reflections suck but that's what the client wanted.)

In the bottom render I scaled the object up 10x in layout, repositioned the lights and camera and set the depth of field to 1.3 m (focused on the terminals), F-Stop 4.0. In this render you can barely see any depth of field effects.

So if your object is many meters across try scaling it down to around 10cm and move your camera closer. You should see the effects of the DOF then.

Shawn Marshall
Marshall Arts Motion Graphics
Portland, OR

03-17-2004, 12:33 AM
thanks all! I got it going with all your help.