Sony FDR-AX1

Sony's FDR-AX1 is notable for being the very first 4K video camera that was designed and made available for consumers, rather than just professionals. It contains much of the same technology that Sony uses for their professional cameras, but with it being placed in a more compact and simpler consumer model.

Its image processor is comparable to that of the professional models and can capture 4K video at a true 60fps with native 3840x2160 4K resolution. This means that it can capture video at four times the level of detail and quality of 1080p.

It also has a 8.3MP Exmor R CMOS image sensor that is back-illuminated, which allows for a maximum frame rate to be obtained when filming. The benefits of this are that you can capture the highest frame possible when filming sporting events or a shot with a lot of movement.

Sony PXW-Z100

The PXW-Z100 by Sony is geared more towards professionals, rather than consumers. It has the ability to capture true 4K footage at a 4096x2160 resolution at 60fps. In addition, it also incorporates a XVAC 4:2:2 10-bit intra frame recording format, which is identical to the one used in the professional PMW-F55 CineAlta Camera that's often seen in the film and television industry.

In addition, the PXW-Z100 can capture 4K footage at a bit rate of 600Mbps, as well as has a G lens with 20x optical zoom, two XQD memory card slots, and 3G/HD-SDI and 4K HDMU interfaces.

Both the FDR-AXI and PXW-Z100 are excellent 4K cameras. Which one you decide to go with depends on your needs!