The A7S II is the best video shooting stills camera available at the moment. The resolution is kept to 12 million pixels to allow better light gathering power and improve video quality. It produces video close to that of professional-level dedicated, but is much smaller and lighter and can record 4K footage internally.

If you don't know, here are some handy specs for the A7S II:

Camera Format: Full-Frame
Pixels Actual: 12.4 Megapixel
Effective: 12.2 Megapixel
Max Resolution: 4240 x 2832
Aspect Ratio: 3:2, 16:9
Sensor Type/Size: CMOS, 35.8 x 23.9 mm
File Formats
Still Images: JPEG, RAW
Movies: AVCHD Ver. 2.0, MP4, MPEG-4 AVC/H.264, XAVC S
Audio: AAC LC, AC3, Dolby Digital 2ch, Linear PCM (Stereo)
Bit Depth: 14-Bit
Dust Reduction System: Yes
Memory Card Type: SD, SDHC, SDXC, Memory Stick PRO Duo (High Speed), Memory Stick PRO HG-Duo
Image Stabilization: Sensor-Shift, 5-Way

And the video formats:
3840 x 2160p at 23.98, 25, 29.97 fps (100 Mb/s XAVC S)
3840 x 2160p at 23.98, 25, 29.97 fps (60 Mb/s XAVC S)
1920 x 1080p at 100, 120 fps (100 Mb/s XAVC S)
1920 x 1080p at 100, 120 fps (60 Mb/s XAVC S)
1920 x 1080p at 23.98, 25, 29.97, 50, 59.94 fps (50 Mb/s XAVC S)
1920 x 1080p at 50, 59.94 fps (28 Mb/s AVCHD)
1920 x 1080i at 50, 59.94 fps (24 Mb/s AVCHD)
1920 x 1080i at 50, 59.94 fps (17 Mb/s AVCHD)
1920 x 1080p at 23.98, 25 fps (24 Mb/s AVCHD)
1920 x 1080p at 23.98, 25 fps (17 Mb/s AVCHD)
1920 x 1080p at 50, 60 fps (28 Mb/s MP4)
1920 x 1080p at 25, 29.97 fps (16 Mb/s MP4)
1280 x 720p at 25, 29.97 fps (6 Mb/s MP4)