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Can the depth-of-field transition be smoothed?

Posted: Tue Apr 19, 2005 12:13 pm
by turner
Hi,

I'm experimenting with the depth-of-field effects and find that as things move into and out of the plane of focus, they abruptly "pop" into and out of focus -

http://www.turnerdesign.net/moho/dof.mov

Can this be smoothed out?

Looked through the manual but haven't found anything yet..

thx
Andrew

Posted: Tue Apr 19, 2005 12:58 pm
by Toontoonz
Have you tried playing around with the Focus Range and Focus Distance in the Project Setting Depth of Field section?

I found that if I increased the Focus Range a bit it kept the things in focus better over a wide depth distance (in front of and behind the 0 point on the z axis).

I found this info in the manual that I think pertains to this.
User Interface> Menus> Moho Menus> Project settings.
It says:
"The focus distance value is the distance from the camera to the plane of perfect focus. Objects that are within the "focus range" distance of this plane will also appear in focus. For this feature to work correctly, you need to set up multiple layers with different depth values so that some can be in focus, and others out of focus. If you move the layers (or the camera) in your animation, the focus will automatically change based on distance from the camera."

Posted: Tue Apr 19, 2005 1:38 pm
by turner
Well, yes, did you watch the test animation?

This is how I have it set up, but as you can see, things suddenly pop into and out of focus, rather than gradually.

I'll experiment a bit more..

Andrew

Posted: Tue Apr 19, 2005 3:07 pm
by Toontoonz
I believe there is depth of field blurring going on and focus blurring going on in your animation. Both need to be adjusted as seen fit in the movement.

Looking at your animation what I am seeing what happens is that your Focus Range is set at "???" (whatever number that is), however your objects are moving through a range of "??? + whatever amount" in the Z axis.
In other words, your objects are moving out of the focus range you set up and then going out of focus. For example, if your focus range is 1 and your objects move in a distance range of 5 on the Z axis, then the objects will go out of focus at some point.
You will notice this happens the most at the end when your objects come very close and behind to the camera view. They have moved through (sharp circles) and out of the focus range - thus getting slightly blurre.

In the Project Settings > Depth of Field try Setting your Focus Range at a higher number (experiment with different values) and see what happens. It should help the focusing blurring.
I had a similar situation and that worked for me.

Posted: Tue Apr 19, 2005 3:34 pm
by turner
No, I intentionally have the objects go in and out of focus -

My point is that the transition between "in-focus" and "out-of-focus" is abrupt - one frame it's completely in focus, next it's completely blurred. The snap is noticeable... It should do this gradually, ideally.

Andrew

Posted: Tue Apr 19, 2005 4:43 pm
by Banterfield
I haven't experimented with blurring in Moho 5, but I've noticed in Moho 4 that there is a noticeable transition between a blur setting of "0" and a blur setting of "1".

For those shots where I need the blur setting to go from "0" to "10", I've taken to starting the blur at "1" and transitioning from there. This crudely takes care of the popping problem. Maybe using depth of field is a better solution, but I like the degree of control I can get by setting blur via key frames, even if it means that I have to start a layer out at the "1" blur setting.

Posted: Tue Apr 19, 2005 4:44 pm
by 7feet
One thing that I notice is that the depth of field, like most of the rest of blur and layer effects, is resolution dependant. The blur radius would seem to be in pixels, so the effect is quite different at 320x240 than it is at, say 1024x768. It also seems to be applied in discrete increments, probably single pixel radius jumps. What I believe is happening is that at such a small resolution, those discreet jumps become really obvious. So a possible solution to minimize this effect is to make the original render of your animation as high a resolution as practical, and then resample the video down to it's final resolution. A larger blur radius combined with a higher resolution provides more steps to increase the smoothness of the transition.

On the jump - Moho determines a layers distance from the camera entirely of the layers origin. As a layer is translated (or the camera) so that the layers origin moves away from the center od the screen, it is also getting farther away from the "camera". It would seem it get's far enough away in those last few frames for Moho to decide it is out of the range of perfect focus. Once again, with high enough resolution this should be a lot more subtle. Hope that helps some.