Sony A7S, Panasonic GH4, Samsunga NX1 are all the best mirrorless cameras in the current market. The Sony A7S is really an amazing camera for both video and still photographers! It features a 12.2-megapixel with a 35mm full-frame sensor, 4K video recording, ISO 50 to 102,400 (extendable to ISO 409,600) and an improved AF system. See best lenses for Sony A7s.
Panasonic GH4 is the world’s first Mirrorless Micro Four Thirds camera with 4K video recording capability and it gets 85% overall score Gold Award at DPReview. See best lenses for Panasonic GH4.
Samsung NX1 4K video recording mirrorless camera gets 87% gold award from dpreview. It features a large 28.2MP BSI APS-C CMOS sensor which can offer high-resolution digital imagery, 4K video at 24 fps, UHD at 30 fps, full 1080p HD video at up to 60 fps. And it has fast DRIMe V Image Signal Processor. Almost every feature on the Samsung NX1 seems to be aimed directly at a class leading competitor, and with impressive results. The NX1 has best in class image quality, best in class video quality, and a lightning fast autofocus system.
Sony A7S vs Panasonic GH4 vs Samsung NX1 4K Video Comparison