How to change shutter speed on manual mode when movie setting is on? I have Nikon d5200. And I am trying to shoot video in manual mode. Movie setting is set to ON from main menu. I can't record video until I switched to live view. And when I switched to live view, shutter speed of my camera sets to 1/50. I can increase the speed to 1/60, 1/80 and so on. But I can't slow it down to 1/40, 1/30 and so on.

Now if I set Movie settings OFF, I am able to change the shutter speed. But actually it doesn't change. I mean it shows on the screen that it is changed but in recorded video there is no change.

Is this the bug of Nikon d5200? Or am I missing some settings? Can it be resolved with some settings, tricks, or firmware update.
If your shutter speed would be slower than 1/50, you wouldn't be able to make a movie.

A movie is a sequence of (typically) 24 or 30 pictures ('frames') per second; so to be able to make 30 pictures, each picture can only take 1/30 of a second. Considering that the camera needs to do some processing and refreshing of the receptors, 1/50 is just enough time to make those 30 shots in second.

You can check if your camera has a time-lapse setting, which means you take less than 30 frames per second, then you might be able to set a slower shutter speed. However, the result might be unattractive because any moving objects would be smeared.