Okay I'm using a DOF on one of my cameras and I have a black circle on top of my footage that appears and disappears. The more you zoom in on the camera the less its visible but its hard to get that focus point. My qustion is why does it appear like that? could it be because of the lens? See photo attached.

Thanks.
Let me know how to solve this problems... thanks!

It looks like you are not zoomed in far enough and are picking up the spindle hub of a disk adaptor.

If you look at the corners of the image, you will also observe brightness falloff, another sign you are zoomed too wide.

If your DOF adapter has an X/Y adjustment, this could also be out of alignment. Having proper X/Y means you don't have to zoom in as much to compensate for it being out of alignment and would possibly make focusing a bit easier, as well.

Okay thanks guys!
Its just if I zoom in a little more it could get out of focus... I guess theres a fine line between the out of focus point and the black spindle!

I'll see if I have the alignment on my camera, otherwise I'm just going to have to get used to it.

Also its weird but when I pan up or down the circle sometimes gets bigger... I used the REDROCK micro... is that normal? Anyone have this system?

The spindle is dipping in and out of your frame because you have image stabilization on. When you pan up or down the lens compensates and the spindle dips into your frame. Turn image stabilization off and see if the spindle circle stays put.

Marcel is on the money...adjust the X/Y position of the adapter on the lens to center on a point further away from the spindle.

Ups, nothing...