Whenever I use long shutter speed, the picture automatically become very bright. But what if I wanna use it for daylight occasions? How to lower the brightness? Usually I can control the "exposure value", but I can't control it if I use long shutter speed.

this camera does not have full manual control i believe?

if so, one way i can think of is to hold an ND filter in front of the lens

Ya, can go until P mode only. So sad. Thx btw.

u can try to lower to exposure, put on a nd filter or use sdhk to get raw files

When u say exposure, u mean exposure value? I can't control that when using long shutter. ISO set to lowest also still bright.

What's sdhk?

custom firmware, google it