I use to connect my raspberry pi to a decline 7-inch screen. It works perfectly. Pay attention to two things though: use the red RCA to connect the screen to make the connection and Raspi WITHOUT hdmi cable connected, otherwise the HDMI will take priority and the recoil screen will remain blue with a beautiful "No. "red signal.
Why the red RCA? simply because the pinout of the Raspi is not quite the same as an example camcorder