Once again, here we are with me talking about a new small camera that everyone in the indie shooting world seems to be going bananas over! Similarly to when the GH4 launched (of which you can read my latest blog post by clicking here) — there has been an extreme amount of chatter about this new Sony camera. Is it worth the hype?
Upon launch, it was touted as the end-all-be-all of DSLR cameras (yes, I know it’s not technically a DSLR!), and a direct competitor to Panasonic’s GH4. Both cameras are mirrorless, seem to have more than a few nods to video users, and come in at a fairly affordable price point. After those features, however, the similarities stop. The two cameras are very different animals — both with their own strange strengths and weaknesses.
The a7s succeeds two other cameras in the Sony lineup that, at a glance, seem the same. The a7, and a7r. The design of these cameras comes from almost a rangefinder idea — a small, street photographers secret weapon. And for stills, no one was going to argue the quality. I’m sure even Fuji was taking notice. When it came to video, however, the quality and feature set wasn’t anything to write home about. While the a7r matched that of the 5dIII in most instances, Canon had already bundled up the market years ago. The a7s, though, has built upon this small form factor and has pushed the video feature set to its ends. It continues with the full-frame-sized sensor, but in this case it seems to be an entirely new chip.
While I’m not in love with the form factor of this tiny camera (I’ve got big, dumb hands), the image quality is staggering. Particularly, with its low-light capabilities. The color and detail data it is able to pull from near total darkness at ISO’s of 20,000 and even 50,000 is unlike any camera I’ve ever seen, in any market or price range. This isn’t just a low-light camera, it’s a night-vision camera. Take a look at this great test from James Miller — that blue sky you see is actually a night sky. Those green bushes? Dark splotches to the human eye.
SLOG 2 & Grading
Now, we aren’t all nature photographers who need to see into the dead of night all the time — so upon getting the camera in my hands, my first tests were tried and true charts. I was overjoyed to see SLOG 2 and S-Gammut profiles included in the kit. This camera is cheaper than a 5dIII, but it’s now including a log profile that was at one time a paid upgrade to the F3 camera?! Count me in! I set up my chart, brought my middle grey down to 35%, and threw on my SLOG2 luts. You know, the ones I’ve been using for the past 4 years! And wouldn’t you know, it looked… terrible.
What?! What happened? Why were my shadows so grainy and noisy? I thought this was a low-light monster! I couldn’t understand it. After some more research and testing, I figured it out.
SLOG 2 on the a7s rates the native ISO of the sensor at 3200 ISO – as opposed to say 2000 on the fs700 and f5, or 1250 on the f55. As this is a different sensor, it is handling its color science differently. I found that it is so light sensitive, the sensor prefers to be fed LOTS of light – to the point of seemingly over-exposing the image. I found that middle grey likes to live around 75%, rather than 35%. As the camera only provides zebras and a meter internally for exposure help, it’s perhaps easiest to set your zebra level to 95% or 100%, and ride the high end until right before clipping. Bringing the color and gamma down works like a charm, and in no time I had the chart performance I had expected:
So perhaps this isn’t the same old same old SLOG 2 I had assumed – but once I figured out the optimal settings, I was very impressed. The dynamic range on this camera is very high, around 14 actual usable stops. That gets into high-end cinema camera territory.
4K Recording & XAVC-S
The last major feature of the a7s is the 4K external recording option. Now, first off, the a7s is using a brand new “consumer” version of the very popular XAVC codec. Internally, this high bitrate and smart compression is very malleable, especially for being at its base an h.264 MP4 file. It sports a very fiddly micro-HDMI port through which it will send 4K, 4:2:2 uncompressed video. The only thing headed to market soon that will handle this in a portable way will be the new Atomos Shogun – delivery date is still TBA.
I find time and time again that users can get hung up on external recording solutions. One should always push their internal codecs as far as they can to see where the line in the sand is going to be drawn, and I find XAVC-S and SLOG 2 to be a 1-2 punch when it comes to color grading. Here is a very pretty video from vimeo user Florian Knab — check out how even the 120fps 720p looks great in a web delivery situation.
With SLOG 2, XAVC-S, a full-frame sensor, frightening low-light sensitivity, and an easily adaptable E-Mount – I think the a7s is a great addition to the indie market. I wish it were able to record 4K internally and high-speed above 60fps at 1080 like its mirrorless GH4 counterpart – but even without these features, it’s a pretty fantastic little camera. If you’d like to learn a bit more about the a7s, my post workflow, and other ways to get the most out of it, be sure to check out my Learning Lab here at Rule Boston Camera on 9/24 at 10am. If you can’t make it in person, you’ll find it on our Learning Lab Vimeo Channel afterwards.
-Alex Enman, Engineer, email@example.com