Yes you can control shutter speed and many other things.
raspistill -ISO 800 -ss 6000000 -o out.jpeg
Will set the ISO 800 and the shutter speed to the maximum 6,000,000 microseconds, or 6 seconds.
Here’s the Raspberry Pi documentation.
I found one not very good solution, which is suitable to my problem for now.
I managed to output the whole video signal (not only the camera video) via 3.5mm TV output. Then I ran a script to make the camera video full screen, and got the camera video on the receiver screen.