As mentioned earlier, I would never use any codec other than XAVC. Not only is editing easier with XAVC S, it also offers the highest data rate and most robust video file to push in post production. The camera does allow dual recording, though I’m not sure why anyone would use that. Even if I wanted to create dailies on the fly, I’d prefer H.264 in 1080p.
Here’s a list of NLEs that support XAVC S, AVCHD and MP4:
- Adobe Premiere Pro CC 7.0 onwards
- Apple Final Cut Pro X 10.0.x via the Sony PDZK-LT2 plugin
- Avid Media Composer 7 via the Sony PDZK-MA2 plugin
- Grass Valley Edius Pro 7
- Sony Vegas Pro 12
- Autodesk Smoke 2014 onwards
- Editshare Lightworks Pro 11
No matter which NLE you choose, editing Sony A7s footage is a breeze. You will never need more than one hard drive (no need for RAID 0) for real-time playback. Even a portable 2.5″ platter drive via USB 3.0 delivers 65 MB/s or about 10 streams of 50 Mbps XAVC in 1080p.
As far as 4K is concerned, the story is different. Prores HQ 4K runs about 110 MB/s. Even a fast 7,200 rpm drive will suffer when you add titles, grades, etc. Therefore, real-time editing and playback demands RAID 0 (at least 3-4 drives) or an SSD via USB 3.0 or Thunderbolt.
- If you’re shooting a 5 minute project with a shooting ratio of 20:1, you’ll have 100 minutes of footage, or 660 GB.
- If you’re shooting a 90 minute movie with a shooting ratio of 10:1, you’ll have 6 TB of footage.
- If it’s a documentary with a larger shooting ratio, you’ll need tons of drives. Here, it might be a good idea to use another codec for acquisition, maybe XAVC (it supports 4K).
Prores HQ is good enough for any kind of editing project, even cinema.
The ‘complication’ in the editing workflow for the Sony Alpha A7s comes in the grading. Let’s look at that next.
To truly understand S-Log2, you’ll need to read my notes from Part Five and understand the fundamental differences between:
If you don’t want to take the trouble, then don’t buy the Sony A7s or don’t record in S-Log2.
Grading S-Log2 is pretty easy and fun. The footage holds up well “under limits”. I have not had any banding or posterization. However, the nature of the S-Log2 curve brings two challenges you need to be aware of:
- Strict highlights that must be controlled during exposure
- Shadow noise
The second is very telling. Cameras like the Sony F55/F5 using S-Log2 have very clean shadows. So does the A7s in stills mode. However, in all the footage I’ve seen so far, either the restricted gamut of the sensor or the heavily compressed codec (including color compression) really gives you a small window in the shadows. It can get noisy pretty fast in the grade and one must be careful. This only applies to the 1080p footage. Once we see 4K images I’ll know for certain.
So, what to do? There are two ways to grade S-Log2 footage:
- Use LUTs
- Grade from scratch
Here’s my honest opinion: Use the latter system in grading. Applying LUTs/presets/effects without knowing what they’re doing is why most people get crappy banding and noise. Some important notes from early experimentation:
- There is an official S-Log2 to Rec. 709 LUT by Sony, but it applies to the gamut of the Sony F55 camera, and doesn’t look all that good with A7s footage. I would NEVER use it.
- If you want to use a LUT right now, then the closest and most pleasing starting place is the Alexa CLog to Rec 709 LUT. It is slightly contrasty, but that can be easily corrected. I would only use this LUT while monitoring, and NEVER for the grade. It is a handy reference to keep within Rec. 709 colors.
- All other camera RAW/Log to Rec. 709 gammas are crap for A7s footage IM-not-so-HO.
- Just as a starting place, I’ve put together a LUT based on the Alexa LUT in Speedgrade. NOTE: Do not use it for critical grading or monitoring. It is just an experiment highlighting what can be achieved. The goals of this look/LUT are to preserve shadow details, preserve white balance, reduce the effects of moire, maintain highlight information, stay in full swing at 32-bit, keep dynamic range and remain within the pleasing range of the Alexa LUT. It is a starting place for further grading. Here’s the download (ZIP, *.look and *.cube) for you to try. Please tell me what you think.
You can use the LUT in Premiere Pro (via Lumetri), After Effects, Speedgrade and Resolve. The transition from full swing to studio swing in Premiere Pro is acceptable (at least to me!).
Overall, I’m extremely excited about the footage from the Sony A7s, even in XAVC S-Log2 mode. It is very filmic (the Rec. 709 mode is horribly video-y).
The Sony A7s has unexplored features for multi-cam editing:
Until I have further information, I’m not going into details here. Just for starters:
- TC refers to timecode.
- UB refers to User Bits. It is eight digits in the hexadecimel system written as XX:XX:XX:XX. The cool thing is you can assign values yourself to this. E.g., in a mult-cam setup, if you have four cameras (C1 to C4), you’re in reel three (R3), scene 12 (12) and shot 4 (04), you can write out the UB code as follows: C3:R3:12:04. This helps synchronize cameras in a multicamera editing environment. Whether or not this is useful remains to be seen.
- Rec flag is a record start/stop flag
Initially, I felt the Sony A7s is capable of genlock via an external recorder. Let’s see if this is true or not. I’m pretty sure the camera will throw up more secrets as time goes by!
This brings us to the end of the Sony Alpha A7s guide. I hope you have found it useful. Please let me know your thoughts and experiences.