4K Ultra HD is 4X greater than Full HD 1080p(2MP), 4K means a clearer picture. It's more than 8 MegaPixels on the screen at once that creates images that are crisper and capable of showing more details than 1080p.
Differences Between 4K Ultra HD and HD
4K - 3840 x 2160p (16:9)
5MP - 2560x1920 (4:3)
4MP - 2688x1520p (16:9)
2MP - 1920x1080p (16:9)
More Monitoring Range
4K CCTV series is also designed to reduce your installation and operating costs through the long range clear image of a single camera.