With Sony FX30, you can record your videos at a highest resolution of 3840 x 2160 at 120p, 60p, 50p,30p,25p,24p fps with bit rates up to 600 mbps and save in XAVC S, XAVC HS, XAVC S-I, H.264 and H.265 formats. Sony FX30's 4K is the common standard resolution in consumer video world.It is also a big step up from its predecessor which has a max video resolution of only. If you are thinking of upgrading your and shoot a lot of video, this is a big factor to consider in favor of FX30.
FX30 features a high speed mode where it captures videos at 240fps which helps to create slow motion videos. If you shoot a video at a frame rate of 240fps and play it back at 24fps, the video will be 10x slower and longer than normal.
FX30 has a built-in Stereo microphone and a Mono speaker. Sony FX30 also has a port for an external microphone and a headphone port for connecting external headphones which make Sony FX30 a very suitable camera high quality videography.
Sony FX30 also features an Digital Video Stabilization mode where videos are stabilized in-camera while you are shooting. Keep in mind that this effect may crop your videos a little bit and doesn't help stabilizing still images. This kind of video stabilization effect can be replicated by using some of the advanced video editing softwares in your PC.