The Sony A7s, along with the Panasonic GH4, are game-changers in the mid- to higher-priced video mirrorless/DSLR space. But hold on there, Slim: the trade-offs are just as real with these two cameras as with any other, and some of them are downright surprising. Today, we look at the Sony A7s 4K recording capability and conclude: huh? Welcome to the next installment in our occasional series called “Dr. Evil’s Sharks with Frickin’ Laser Beams.”
Sure, the A7s and Shogun combo costs more than twice as much as the GH4 (which records 8-bit 4K internally) and it’s a whole lot bulkier, but holy smokes: for that, you get everything the GH4 is plus that full-frame sensor with razor-thin depth of field, knockout 14 stops of dynamic range and high ISO performance that is unrivaled at anything remotely near that price point!
It turns out that even at two and a half times the price, one of the things the A7s doesn’t do is 4K 10-bit color: it sends an 8-bit 4:2:2 signal through the HDMI cable to the Shogun.
Sony Outputs 8-bit. Not 10-bit.
That’s right: 8-bit. Not 10-bit, like the GH4 when it is connected to the very same Shogun (supposedly – we will see once the Shogun is actually shipping).
But let’s back up a minute and acknowledge a not particularly popular or well understood truth: 8-bit is all you need between 95% and 100% of the time – unless you’re always shooting landscapes early in the morning or late in the afternoon; you shoot a disproportionate number of high contrast back-lit shots; or your primary output is to the web.
Or Blu-Ray, for that matter.
It’s that incredibly fine, progressive gradation in the sky, or the similarly fine, progressive light fall-off from a bare bulb just behind the axe-murderer standing in the doorway that makes 8-bit capture with its 256 shades of color cry “momma” – and where the 4x tonality of 10 bit – 1,024 shades – comes into play.
So the question becomes: do you actually need 10 bits? Only you know the answer.
But if you’re someone who really cares about dynamic range, high ISO performance, 4K, and shallow depth of field, I’m betting you might.
By the way – did you know that you can set the GH4 to 4K; set it to auto down-convert to 1080p; and then send a 10-bit 4:2:2 signal to the Shogun’s little brother, the Ninja Blade, in ProRes?
(cover photo credit: snap from Hugh Brownstone)