Jello can occur when you film in bright light, because the camera will choose a high shutter speed, try fitting a ND filter, the higher value of the ND filter you use the slower your shutter speed will be.
Your shutter speed should be around twice your FPS rate, i.e. 25fps your shutter speed should be around 50.
Your shutter speed should be around twice your FPS rate, i.e. 25fps your shutter speed should be around 50.