I used to think that setting the parameter to 40 is not to blur and setting it to less that 40 is to sharpen it, but in fact setting the parameter to 0 is not to blur and setting it to 40 is to blur a little. In order not to mislead others, please set the default value of Blur to 0. Thanks.
Thanks for report and sorry for huge answer delay. Since then effects & default values have been reworked...