Would bypassing AF100 to Atomos Samurai give me better results for chromakeying???

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Nicholas Natteau

Veteran
If my green screen scene is properly/evenly lit, will it I get much cleaner results bypassing the AF100 AVCHD codec and recording to Apple Pro Res via the Atomos Samurai?

I've heard many people say they great keys using only the AF100 so long as the green screen scene is well lit.

But do you get much better results using the Atomos Samurai or Ki Pro Mini?
If you're recording straight to Pro Res, will it be much easier to pull a clean key?

Thanks in advance for your feedback.
 
Shooter's the man....

if you wanna get the best results .. you can go uncompressed to a hyperdeck shuttle...
although you'll blow through media like nobody's business.

jeff
 
Jeff...I am not sure if the Hyperdeck would actually produce even better results because I do not know what the uncompressed format in the device records the samples as.

eg 4.2.2 or 4.4.4

If any one does know please advise.

Meantime... 4.2.2 will always be better than 4.2.0 for post work (then take into account 8 bit vs 10 bit)


"horses for courses" - dont under estimate what we can achieve with the native files off the AF100. They are pretty impressive.
 
It's 4:2:2 / 10bit in a REC 601 or 709 colorspace ..

Although with a CMOS sensor, I wonder if the compression artifacts
would matter when keying.

jeff
 
It is my experience/understanding that the AF100 outputs uncompressed 8 bit 4:2:2 from the SDI port. The Hyperdeck records this in a 10 bit 4:2:2 file.
 
Shooter said:
"horses for courses" - dont under estimate what we can achieve with the native files off the AF100. They are pretty impressive.
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To the OP, I shot some green screen two weeks ago with my HMC150. I handed the footage to the producer, and he said he was easily capable of pulling keys with it without issue. So long as you light it well(!) you should be fine with the native footage of the AF100. The Samurai should be better, but the AF100 native footage will still be pretty good.
 
Thanks very much everybody. I agree Mike. I've had very good results with my AF100 after dialing down my sharpness settings.

I was always getting terrible buzzing/noise/artifacting around the edges of my subject until someone told me to turn down the sharpness settings on my AF100 for chromakeying. I got much cleaner results after that. That's why I wonder if using a device like a Samurai wouldnt give me considerably cleaner results.

Is the noise around edges caused by the compressed nature of the AVCHD codec? I'm using Adobe Keylight 2.0 to chromakey.

Regarding the Hyperdeck shuttle, how would that give you better results than the Samurai? Isn't the Samurai Apple ProRes 422? I read that the hyperdeck shuttle features 10 bit 422, but I also read that AF100 only allows 8 bit out on the SDI port. Am I mistaken?
 
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Just did some chroma keying with AF-100 internal codec. Had AF on my "low noise" camera profile and the keys were very good. By very good I mean the client loved them. I did take care with the lighting of the "blue" screen (yeah I know I gotta get one of those "green" screens but never had any issues with my old "blue" one)
 
Nicholas,

You are correct, the AF100 only outputs 8-bit 4:2:2. Recording into a 10bit recorder, won't improve the quality. In theory the Hyperdeck should get the best possible image as it is not compressing the image at all, no codec, no compression artifacts. The ProRes recorders are compressing so technically there will be some loss in quality. But in practice, I've not been able to see any visual difference at all between my Hyperdeck and PIX 240. I would assume the Samurai would be similar to the PIX as they share the same compression codec, but I haven't used one myself.
 
The thing that makes the general difference for an improved chroma key (and I.Q) is the last digit in the color sampling line. 4.2.X

4.2.2 vs 4.2.0

10bit vs 8bit is a four-fold difference but I have no way of knowing what technical advantage or otherwise happens when an 8 bit signal is recorded by a 10bit device. I assume it is padded but dont know how that works except...working in a 10 bit space such as Da Vinci Resolve , it is superior to any other cc / grading experience.

This manufests as the subtlety of hue, luma and gamma control.
 
Thanks again everybody.

Stephen, if you were to record a properly lit green screen scene with two AF100s: one connected to an Atomos Samurai recording the footage as AppleProRes HQ and one connected to a Hyperdeck shuttle recording the same footage as uncompressed 10-bit ...

Would the uncompressed footage from the Hyperdeck give you even better/cleaner keys (because it's uncompressed) than the slightly compressed Apple ProRes HQ footage?

Just asking because I'm trying to decide which device to get...the Hyperdeck shuttle or the Samurai.
 
Nicholas. If you are shooting Lord of the Rings or Avatar...go uncompressed.

But...your decision maybe needs to consider the hardware and the way it functions for your purpose as well.

Download the User Manuals of each device and you will see the differences. The Samurai is far more versatile and has many useable functions. The HD Shuttle is a manual Recorder with only REC On/Off and replay. No user settings at all ( although the MK2 will have a couple for codec choice obviously)

Do consider your post production workflow. Uncompressed footage is massive eg 120GB = 11 minutes (ish).

Here is one way I use the Samurai. as in a shoot last week.

Dual Record to Internal and external.
The clips are setup to be numerically identical with in the file names eg 00032.mts = jobname_32.mov
The AVCHD goes into my NLE
The SSD from the Samurai goes to the Flame Compositor Suite
I edit and supply EDLs which are edited to conform the filenames and clip locations

Huge pluses:

End of a days shoot...having footage on two devices is of considerable value to my piece of mind.

We wrap faster - no backing up at the studio / location.

Post house which is Mac based does not have to transcode and rolls straight into post.

Post house prefers the 4.2.2

Insurance company loves the security of the data.

My HD Shuttle is now consigned to be only used for CGI work or SFX.

When I get a second AF102 body - I will get a second Samurai.
 
Well said Shooter.

The big visual benefit comes from using an external recorder as it gets you a 4:2:2 stream. The visual difference between the external recorders is smaller.

I use a PIX 240 for similar workflow benefits that Shooter gets from his Samurai. In my opinion the primary reason to buy the Hyperdeck is price. The only reason I have one is that is shipped first, before the other SDI recorders. That said, for the money it's pretty amazing. It's cheaper than most HDMI - HD-SDI cross convertors including Black Magics own.
 
Thanks very much Shooter and Stephen for elaborating on these points. I think I'll go with Samurai after all then. This has been very helpful advice. Thanks again!
 
Nicholas Natteau said:
Thanks very much Shooter and Stephen for elaborating on these points. I think I'll go with Samurai after all then. This has been very helpful advice. Thanks again!
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I also have to mention that the customer service at Atomos is second to none. I just got mine thrusday and I hit a little snag with my samurai when it arrived, but they really pulled out all the stops and really went above and beyond to make sure I was up and running in time for my shoot this weekend. For that reason alone, I have to say I recommend them above all others personally. I will post a little write up of that story later once we wrap and I have time to type it out, but suffice to say Atomos is really amazing.
 
OK then I'll be getting the Samurai kit from B&H, the one that comes with a 160GB SSD drive.

Does anyone know how many minutes you get with 160GB SSD drive if you're shooting 1080p24??? If it's half an hour that's fine. If it's only 10 minutes, then I'd definitely need a bigger drive.
 
Oliver Rush said:
I also have to mention that the customer service at Atomos is second to none. I just got mine thrusday and I hit a little snag with my samurai when it arrived, but they really pulled out all the stops and really went above and beyond to make sure I was up and running in time for my shoot this weekend. For that reason alone, I have to say I recommend them above all others personally. I will post a little write up of that story later once we wrap and I have time to type it out, but suffice to say Atomos is really amazing.
Click to expand...


It's good to see Atomos get the kudos they deserve, because the cynicism when they first announced the product, and then had delays, could have buried them as a company. They delivered what they said they would, and then the Samurai came too.

I want one, but I need to save.

What happened to Dave Shapton though, as I understand he left, but he was the main voice in those early days?
 
electricpig said:
What happened to Dave Shapton though, as I understand he left, but he was the main voice in those early days?
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Yep. I pre-ordered because of him and stayed (relatively) cool when shipping was delayed.

Apart from that: Not having had the time to really give it a tough ride this machine still amazes me. Extremely easy to handle. No frills. Great. And if they really treat this as a "platform" that can develop through firmware upgrades and can have other features implemented they'd be an example for manufacturers of cameras who should - when- and wherever possible - take the same approach imho.
 
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