Shutter Speed has no effect on motion blur

Hi,

Currently, I am using UE4 to render a movie to a video sequence. I have found that in UE 4.19, there is a new exposure function called “Manual” which can allows you to adjust shutter speed, ISO, aperture, exposure compensation parameters.

I just want to use shutter speed to control the strength of motion blur, i.e. the higher shutter speed the lower strength of motion blur will be obtained, but unfortunately, when I increase the shutter speed of the camera in UE4.19, the strength of motion blur does not change… I don’t know why…

Could anyone please can help with this strange problem?

Many thanks!