Note that effect works with the special custom shaders in the package listed below. It can work with your custom shaders only if you add depth to your shader

This asset consists of shaders for applying the depth of field to the scene.These approach is among the fastests in the market. During development the main goal was to maximally optimize the well-known depth of field technique, keeping the quality of the final image. The shader was tested on the low-end mobile device in a loaded scene.

SHADERS

* DOF – The fastest depth of field shader in the Asset Store. Runs at 46-55 fps on low-end device.
* UnlitDOF – Modified and optimized version of standart mobile Unlit shader.
* DiffuseDOF – Modified and optimized version of standart mobile Diffuse shader.
* SpecularDOF – Modified and optimized version of standart mobile Specular shader.
* TransparentDOF – Modified and optimized version of standart Cutout shader.

NOTE!!! All the testing was made on low-end mobile device Meizu M2 Note in the scene containing:
-65 different gameObjects,
-68 different Materials,
-57 different Textures,
-1 Directional Light(realtime),
-approximately 40k polygons