Focal Depth keep jumping to different points while rendering

[onebleep]

Using R20 , Octane 2018

I used the ":Pick focus" icon to find the area where the camera needs to focus, but when I render it starts focusing on the right point but then it jumps to objects in the back and then back to the front again. I've tried this now with autofocus on AND without, do I need to keyframe the Focus depth? It looks fine in viewport or am I missing something?

[aoktar]

Most likely you missed something. But how can we know what's that?

[frankmci]

I find it most reliable to use an Xpresso Distance node to calculate the distance between the camera and a child null. That way it's easy to see exactly where the focus is, and easy to animate it without fiddling around with numbers. You can also just plug the C4D camera's Object>Focal Distance into the Octane Camera Node's Thinlens>Focal Depth if you're more comfortable setting it that way, but that only shows you the center of a focal plane, not the true, spherical focal distance. With a null, it's easy to keep non-centered objects in proper focus.