AF100 noise

Steve Kahn

Steve Kahn

Well-known member
First off this isn't a slam. I'm not trying to put this camera down. Far from it. I'm #3 preorder and will be getting one of the first ones made. My question is in the interest of learning about the camera I am soon to own.

When Leo and Barry shot some footage there seemed to be an unusual amount of noise in the blacks. Was it the camera? Was it our monitors? That was the big disagreement with Barry ending up stating it was us, our monitors and not the camera. To many of us this made little sense because other footage we had seen never demonstrated this kind of noise.

Then a week later I know Timur said in his blog when he first started playing with the camera in NY that the noise he first saw was removed by taking a black balance and after doing so he felt comfortable shooting at ISO 640-800 and saw no noise. We infact saw a ISO1600 night shot he took which was very clean for 1600.

Then we saw Stephen's beautiful trailer which Timur shot as well. No noise. But, before he released it Stephen said he needed to do certain things to optimize the clip for net viewing.

So mu questions:

Was it indeed a black balance issue that created noise at ISO 400?

If so how often and under what circumstances must one black balance?

Timur, other than maintaining a proper exposure and nit using DRS, were their other settings on the camera that you found to help reduce noise?

Stephen, do you mind sharing your workflow - specifically how you compressed for the net - with your great trailer?
 
It's the opposite of white balance. lol Im just kidding you. To be honest, I have never black balanced either. But Im assuming you shoot a black card and tweak the cam till the black is where you want it. I dont know. Im eager to learn though.
 
Like the HVX, black balance is executed internally by the camera closing the iris and then it calibrates. I am curious how the Af100 does this if there is no iris.
 
It's one of my pet peeves when I hire operators that don't black balance every-time they white balance (or more often)… Very surprising how few 'competent' and 'highly regarded' camera ops even know what a black balance is.
As far as I'm concerned, it should be done often - It lets the camera know where both ends of the scale are.

G.
 
Additionally, at least with many 2/3" cameras, black balancing can mask overcharged or dead pixels. This is best done after the camera has had plenty of warm up time.

I am curious about white and black shading issues, does the AF100 have any kind of shading circuits, auto or manual? This would seem to be more important with a large sensor camera that uses a wide variety of lenses, the majority of which are not designed for video cameras in the first place.
 
However, the imagery that Barry and Leo shot did not have a noise problem. It is beautiful. I fully believe that the issue was that the folks complaing were dealing with something that FCP or their computer was adding in, and they didn't know how to get around it. I took the footage that Joe Walker posted as a ProRes.mov ad put it back into a timeline. I then sent it out via HD-SDI and recorded back to an SD Card. This is the footage I showed in Chicago. There were no complaints of noise, just oh wow, that is gorgeous.

If I could figure it out and post what to do about it when that situation happens, I would be rich, but I actually don't believe it is the same for everyone.

Best,
Jan
 
I also took Leo ProRes clip into FCP - it did have plenty of noise.
I took the "Versed" trailer and even after converting it to ProRes
it did not have the noise patterns I saw in Leo's clip.
The noise patterns in Leo's clip looked a lot like HVX200 noise
when the gain is turned up.
I also took Leo's ProRes clip and made an mp4 and compared it
to the mp4 they posted on Vimeo - it looked the same.
On a Samsung 40" LCD it looked better but you could
still see noise.
Thus when I saw the "Versed" trailer I was somewhat relieved
but I will hold any judgement until I see more footage.
 
The workflow in FCP for the "Verse…" trailer was pretty straightforward.

- Log & Transfer Clips into ProResHQ
- Edit
- Output Master Sequence in ProResHQ
- Import Into Color for Grading
- Output Final Full-Res Master in ProResHQ
- Prepare for Vimeo in Compressor (6000k H.264 Encode Settings)
 
Stephen, do you agree that there was visible noise on Leo's test footage? As someone stated, it's just hard to buy the monitor issue since your stuff and other AF footage we've seen, shows much less (or no) noise on the same monitors.
 
Apparently the af100 has a light tight shield that slides down over the sensor when you black balance.
 
As Timur described to perform a black balance one must half depress the white balance and hold for five seconds I was wondering: could a user defined button on the camera be dedicated for black balance?
 
I fully believe that the issue was that the folks complaing were dealing with something that FCP or their computer was adding in, and they didn't know how to get around it.
Click to expand...

Fair enough. That may be possible. But then the issue becomes workflow and we have a question to address: what is a clean workflow for computer monitors and the net?

Still, I hope you are wrong and Timur was right. It did seem that performing a black balance fixed things.

Barry & Joe: what was your workflow if you don't mind sharing?
 
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Jan_Crittenden said:
I fully believe that the issue was that the folks complaing were dealing with something that FCP or their computer was adding in, and they didn't know how to get around it.
Click to expand...

We would not know if that was the case unless we could get the original AVCCAM file. If Joe can post one of the files with the fruit or flowers that would be great.
I have edited with FCP for over 5 years now. I have posted jobs using P2, XDCam, files from 7D's and stock footage from dozens of sources and have never
seen the noise I saw on the AF100 sample footage that Joe posted.
 
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