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Old March 14th, 2011, 10:45 AM   #1
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Discussion: add gain in pre- or post- ?

Not pretending that I've not been inspired by this thread on the other forum:

Is it better to use a high gain or colour grade after when filming in a dark venue?,

- I'd like to invite all nanoFlash users (and CD themselves) to a similar discussion. It is even more relevant in the context of relatively noisy cameras (like the EX series), and the high bitrate offered by the nanoFlash.

Comments and opinions welcome!

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Piotr Wozniacki is offline   Reply With Quote
Old March 14th, 2011, 11:08 AM   #2
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Re: Discussion: add gain in pre- or post- ?

It is hard to discuss it without performing some actual tests. Before I got my nF, I tried higher gain in my EX-3 and the results were horrible. Way too much noise. I have been in poor health for the last year or so, so I have not been able to do similar tests with the nF connected to the EX-3. But the only way to have any meaningful discussion, IMHO, is by trying it and seeing what gives you better results. And then by sharing those results with the rest of us.
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Old March 15th, 2011, 06:36 AM   #3
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Re: Discussion: add gain in pre- or post- ?

Gain is an option to avoid to miss a shoot because poor lighting conditions, and the only rule is to apply the less possible, because Gain damages the picture.
How much to apply?
No formula. That you will only learn it with your experience shooting with Gain and trying to fix things in post.
What I don't see is the NANO as a factor on dealing with camera gain.
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Old March 15th, 2011, 06:52 AM   #4
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Re: Discussion: add gain in pre- or post- ?

Better to use all the tools at your disposal in your EX to get the scene as bright as possible. STD3 or STD4 gamma, 720p, set to shutter speed and dial the shutter as slow as possible and put flicker reduce on, if able to tweak gamma settings on location in your picture profile settings and boost the gamma in post using as high a bitrate and bit depth as possible in your post transfers.

A few tests should tell you this is the way to go.

Boosting the gain on the EX beyond 3 dB will give you horrible results that you cannot remove from source. Do some short tests indoors, if you haven't already and you will plainly see.

BTW low light generated noise in 1080 is not a pleasant sight and you loose the equivalent of a stop or two in relation to 720p, so you get doubly penalized for using 1080 in low light.
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Old March 15th, 2011, 07:35 AM   #5
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Re: Discussion: add gain in pre- or post- ?

I've been meaning to run tests on this myself, and hopefully I will get around to it soon.
My camera (XLH1) is probably worse than the EX1 in terms of noise. It seems the Nano can amplify this if you're not careful.
Where possible I always shoot at -3 gain.
If required I bump it up to 0 gain.
I usually have a PAG light mounted on the camera so this will be used next for running-and-gunning.
Before bumping up to +3 gain I would usually reduce shutter speed from 100 to 50 or down to 25 if there is not much camera movement expected.
At +3 or +6 gain I usually use a preset I have worked out for my particular camera in the settings. This usually means dialing down the detail, dialing up the core, and using the internal noise reduction filter (NR2). The internal noise reduction filters work to a degree (although NR1 can cause unusable 'trailing' images, so I usually stick to a low NR2 setting which flattens the image somewhat at the expense of detail).
Pretty much anything above +6 gain is terrible with all of the above settings, in which case I switch the camera off (unless the event being filmed is so brilliant that the quality does not matter).
I need to do more tests with the above variables, and try to fix the above variables in post to see how far they can be tweaked.
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Old March 15th, 2011, 10:42 AM   #6
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Re: Discussion: add gain in pre- or post- ?

A few days ago, I rode along with 2 police officers with my EX3 but no nanoFlash due to size and room constraints. But, the light was very low so I used 720 30p, 180 shutter, 9db and a custom PP that greatly reduces noise - Frequency, Crispening and a 3rd setting were greatly adjusted to reduce noise. Black Gamma and Black were +10 & +15.

FYI, Neat Video works wonders in reducing noise in post. I have tested this plug-in with 50Mb & 100Mb nanoFlash footage and its the perfect combo to the nanoFlash. If you must do some extensive grading or effects, a great process is to use After Effects, Neat Video and Cineform (or Pro Res). There is a great tutorial in the Cinefrom forum showing how to make 5D/7D video look so much better with these 3 programs.
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