A new (and extraordinary) Sony A7S 4K low light test


The Sony A7S is the camera I am most looking forward to in the coming months and although it is a shame it lacks an internal 4K codec, it does promise much improved internal 1080p and 4K HDMI output. Here Yosh Enatsu has used the Blackmagic HDMI to SDI Ultra HD converter to a Hyperdeck Studio deck to record this test shoot in the dead of night.


Here’s the A7S rigged up to the Blackmagic converter and the Metabones Smart EF adapter for Canon lenses.

The ergonomics of this rig are poor, but right now before the Atomos Shogun ships it is likely the most high quality way of getting at that beautiful 4K HDMI output.

ISO comparison

Yosh also shot an ISO comparison, increasing from ISO 800 to a maximum of 409600. Just bear in mind that YouTube compression, even in 4K, acts as very heavy noise reduction. I’d love to see some source files in ProRes or at a high bitrate of H.264 to see how much fine grain there is in the output as the ISO increases.


This shot from Yosh gives you an idea of just how dark the location for the shoot was…


Earlier the team setup the Blackmagic Hyperdeck Studio on location…

Small camera, not so small setup!



The A7S looks fantastic with 15 stops dynamic range, great stills, huge EVF and that incredible low light performance will mean new creative possibilities.

The only drawback for me, is that to feed that huge sensor you generally need large lenses and to get at that 4K you will need to bolt on the recorder. I just know I’ll be using my fast Canon L and Sigma ART lenses on the camera and attaching the Shogun. Such a tiny camera body in that situations begins to feel a bit silly.

To maintain the size advantage and general ‘balance’ of the system you would need to invest in a set of Leica M primes and fall back to the internal 1080p codec… those lenses would be a considerable expense, more than the cost of a Canon 1D C, maybe even a Sony F5.

Still if the image is worth the spidery rigs and added bulk over the GH4… I’ll forgive that pretty quickly.