how to reduce clump of strange noise in render? I have a strange clump of pixels on a model added into some video. am experimenting with animated depth of field to get the model to defocus when the camera does, the pixels stay in focus and seem to accumulate through the short test clip they are not static they move around in the one spot on each frame. the material is trying to look like a glass ball of a solar garden light. now that I look I can see it rendered in the camera view of the viewport too both can be seen in the image. is there a cure for this?

this is the material , the image used to map is a photo of the glass ball.

fixed with help from Gordon Brinkmann.
It looks like noise from reflective or refractive caustics or something simlar. Try disabling &quot;Reflective Caustics&quot; and / or &quot;Refractive Caustics&quot; in the Caustics section under &quot;Light Paths&quot;. If the noise disappears, try re-enabling caustics and in the &quot;Clamping&quot; section set a value for &quot;Indirect Light&quot;, like 10 or 5.