When there is no specific object to detect, ie scene with stones pebbles etc in the foreground, or branches in a tree. Adding enough sharpening on the in-focus areas causes halos in the out of focus.
For example, a slider that says beyond this blur reduces noise/sharpening applied blur-based object selection. My workflow deals with this by having a sharpen/ noise reduction layer and none sharpen/ reduction layer in Photoshop and masking.
