4K Footage - XVAC-S S-Log2 From a Sony a7s and an Atoms Shogun

Today I received my Atomos Shogun 4K recorder/monitor and quickly set it up and shot a few seconds to test everything out. Below is the footage - first S-Log2 with no grading, then side by side, and finally full screen graded footage.

This is by no means a comprehensive review of S-log2 and the Sony a7s, I am merely sharing my first video testing.

Sony a7s Full-Frame 4K capable with external recorder like the Atomos Shogun

As most of you know S-Log2 is supposed to give you more dynamic range then Rec. 709. I've read some users claim excessive graininess or noise depending on how S-log2 is exposed.

I mostly eyeballed the exposure. These were +2 or more stops overexposed. I am going to delve deeper into this profile and experiment more closely to see what happens at different exposure settings.

Stay tuned...



I would like to be clear here, I have NOT been given any of these products in exchange for positive reviews. These products have all been purchased and payed for by me with no help from these manufacturers.

Sony a7s and some S-Log2 XAVC-S footage

I know I said I didn't care for the DSLR form factor. Mainly because DSLR's don't normally have all the features of a dedicated video camcorder, and because you have to purchase all the extra DSLR "rig" stuff. Like a matte box, and a whole rail system with a cage, and on and on.




Well, I got tired of waiting for Sony to release an interchangeable lens 4K video form-factor camcorder, that wouldn't break the bank. I'm sure there's one in the works, but I can't wait, besides I needed a new still camera anyway.




I purchased the Full-Frame Sony a7s camera to replace my NEX-VG900, and to get started shooting 4K video. I don't have an Atomos Shogun recorder yet but in the meantime I shot some 1080p footage using the XAVC-S and S-Log2 profile.

This is a short video shot using the Picture Profile 7 which is S-Log2. I didn't have any luck using FCPX built in Log Processing, under the Info tab in the Inspector window. I graded using FCPX's built-in Color Correction. Sorry for the shaky video.




You have to overexpose slightly or else you get noise. The lowest ISO for Profile 7 is 3200. If you are going to use this, experiment with it first and shoot plenty test footage. You may need an ND filter if you want to open your iris and shoot narrow depth of field. You can also increase shutter speed to something outrageous, you just won't get the 24p movie blur, when you pan.




The S-Log2 stuff looks flat and low contrast out of the camera and it must be graded, unless you like low contrast flat video. I guess the idea is that you have more range for grading. 

I believe this is 8bit S-Log2. I wonder if I can shoot 4k and down-convert to 1080p 10bit S-log2? As soon as I get my Atomos Shogun I'll post more footage - 4K footage, and I'll see if 10bit 1080P is possible from 4K footage.

Below you can appreciate this small camera surrounded by stuff just to make it more video friendly. I'm still missing the Shogun from Atomos - I'll review it soon - and more on shooting 4K on the a7s.

a7s with all the fixings - Atomos Shogun coming soon

I would like to be clear here, I have NOT been given any of these products in exchange for positive reviews. These products have all been purchased and payed for by me with no help from these manufacturers.