There are currently four ways to record 4K from the Sony A7s:
- Atomos Shogun ($1,995+)
- Convergent Design Odyssey 7Q+ ($2,295+)
- Blackmagic Design Ultrastudio 4K ($945.25)
- Blackmagic Design Intensity Pro 4K ($199)
The most inconvenient way for field use is the Ultrastudio 4K, which needs a rack system. The best bang for the buck is the Atomos Shogun.
The cheapest is the newly launched Blackmagic Design Intensity Pro 4K:
Obviously, you need a computer with this thing, because it is a PCI-Express card. To work in the field, you can either use a Windows machine that houses this, or use an expansion chassis, like the Akitio Thunder2 PCIe Expansion Chassis ($219.99), for Macs (also sold rebranded as OWC):
It’s not small, but you can connect it to a Macbook Pro, iMac or Mac Pro in the field. So, if you already have a laptop, the cheapest way to record 4K is to use an Intensity Pro 4K card ($199) and an Akitio expansion chassis ($219.99) = $419.
The smallest footprint would be to use a small Windows machine or Hackintosh in an HTPC enclosure like the hec Black Media Center with 300W power supply ($60). You will need to build your PC with a Micro ATX motherboard (like the ASUS Q87M-E/CSM ($123), an i7 processor, RAM, etc.
What are the main disadvantages of going this cheap route?
The main disadvantages are:
- They are bulky and difficult to travel with
- They need cables and computers to run
- Your camera is always tethered to your laptop
- You need an external AC power outlet always
If you’re in an indoor-always studio environment, this solution is perfect.
What are the main advantages of the Shogun or 7Q+?
- You get a full 100% Rec. 709 field monitor
- You get 3D LUTs
- You get to record in Prores or DNxHD
- Your system is totally portable and small
- You can power the device using a small battery or one power solution for your rig
- You have scopes and other important reference tools
- You can record and monitor audio as well