Resolution is only half of the story for video camera specs – you also need to know the frame rates available. If you live in an NTSC region you need to be able to shoot at 30fps. If you live in a PAL region and you plan creating video for PAL devices, then 25fps is best. If you're creating video for online or computer playback then this is less important – 30fps is an effective default frame rate for smooth-looking video. Some cameras can also shoot at 24fps which is the frame rate traditionally used in cinema – fans say it gives a 'cinematic look', but there's nothing inherently more creative about it, it just subtly alters the appearance of movement.
Some cameras offer faster frame rates, and these will usually be in multiples of 25fps and 30fps – so a high-spec DSLR or CSC might also offer 50/60fps frame rates. This is so that you can play back at half speed to get a slow-motion effect but still get 30 frames per second and a smooth look to your video.
The combination of high resolution and high frame rates needs a lot more processing power, which is why some cameras (action cameras, for example) will offer higher frame rates but only at lower resolutions. the GoPro Hero4 Black, for example, can shoot 4K footage at up to 30fps but can shoot 1920 x 1080 full HD at up to 120fps. If you play this 120fps video back at 30fps, you get a quarter-speed slow motion effect.
