Scene Files=Grain?

[Car3o]

Has anyone ever had grain issues with their scene files? I got a new screen today and noticed no grain, but when I changed the scene files, the grain was very apparent. What do you think? Who has a vibrating adaper they can try it out on?

[Reese-015]

You're talking about seeing no grain on the screen while shooting and even while logging but seeing a lot of it in the saved avi's? I have that all the time.

Anyone know what causes it?

[Mtech]

Frankly more sharpening (detail level) and more contrast (master pedestal) will make any grain more apparent.

[Jason Ramsey]

Less detail. Go into the negatives on your Master Ped. Choose a less noisy gamma setting. Like B Press, or High. The Cine Gamma curves will be more noisy. Cine D being the noisiest. I love Cine V, personally.

Learn the limitations of your camera. These small chip HD cams aren't going to give you the low light performance that you can expect from their SD counterparts.

Don't trust your computers LCD regarding your picture quality. Looking at it on a HDTV (or properly calibrated production monitor) will yield much better results.

Oh. And 35 adapters will suck the light that would otherwise be getting to your camera. In otherwords, if you are using an adapter, you are going to need a lot more light to get acheive comparable results from the same scene without the use of an 35 adapter.

Jason

[Car3o]

If I were to not use any scene files, on my lcd or avi's the scene's are practically grain free when using a 35adapter. I play around with the settings and the grain becomes very apparent. Dunno why. If I come across the scene files again I'll post the differences.

[jamestmather]

The key to grain reduction in any format is light - cameras feed on it and, when starved of it, will punch you right in the grain. The old film principle of shooting using more light and effecting a slight crush in post is the best option - treat the HVX settings as though they were a film negative is my suggestion -

In other words don't crush in camera - hardly any DPs in the film/video world would opt to do that but rather gather as much information as possible and then do it in post - Set your mode to BPress for example. (CINE D and V are the noisiest and also chuck detail away at the bottom of the "curve" (or the exposure range (since video has no real "curve").

Turn your detail coring up a little - but check your avis on a hidef display so they don't get too spongy. (I really recommend Barry Greens HVX book for those of you interested in the finer workings of the HVX - surprisingly readable too). balance this with the detail settings. find a midway you're happy with,

turn off all your auto gains etc on the hvx - make sure that the AGC is off - otherwise the lil' camera might undo all your good efforts.

Finally - overlight - for 15 years I have been doing this as a film DP (overclock the neg a little (something I suspect the latest Kodak stocks do automatically - the devils) - For comfort try to crush your camera display settings down a little if you want a visual reference (in other words darken your camera monitor settings so that when you overlight it doesn't look garish and make you nervous - test this until you get a nice parallel with your final output) . Overlight about half a stop to a stop is good - watch highlights clipping out (100% on the zebra) - nothing gives away the video look quicker and once they're gone - they're gone.

In post crush your avi down in post using "levels" or "curves" (or 55mm do some great filters to help in this regard which deal very organically with this.)

Once you have done this post-crush, try to balance your on camera monitor to the final graded output in after effects (or your CC package). ie; drop your P2 back in and balance them by eye until they look similar (now you can light a "dark" scene but know that the "neg" is getting a lot of wallop.

Set up your crush as a preset in your NLE or AFTER EFFECTS and apply it as a matter of routine to your incoming footage. (that way it won't come in super bright and cause momentary heart failure)

Viola - less grain - plus please TEST all the above thoughts before using them on any job which might lose you money/reputation. Everyone is different and might hate the system. but it works for me.

[AshG]

Actually, crushing the blacks a little will help reduce grain. It is at the expense of loss of detail in shadowy areas but for many applications, people love the look. In DV world one might argue that you are better off getting as close in camera as possible to the final look you want to avoid more lossy compression in post...



ash =o)

[jamestmather]

Yes but crushing in camera means you have nowhere to go later - we're not human telecines and you will need to grade your footage somewhat - I say always go down, not up - in terms of "getting it in camera" excessive colour correction is to be avoided but in terms of contrast I find that it's better to err on the side of letting the camera gather what it can and crush later (just like film - overexpose and print down is a long held mantra) - thereby avoiding camera induced artifacts like macroblocking (if what you say is true then cine D should be the most grainless and yet Bpress is clearly less grainy as it's lowering the contrast). I'm not suggesting a low-con final look - they will look the same in the end but the post crushed version will be cleaner.

My own tests have completely eliminated grain from the HVX but if you're a crush-in-camera guy and that works for you, then stick with it. :)

[AshG]

Film and 1/3" CCD video are different animals. With the dynamic range of film you can afford a hotter picture, you should never overexpose video, it goes to pure white too quickly. Personal preference I guess but pure blacks look less egregious than blown out white which just scream cheap video.


ash =o)

[jamestmather]

Ash, I refer you to my first post above -



Overlight about half a stop to a stop is good - watch highlights clipping out (100% on the zebra) - nothing gives away the video look quicker and once they're gone - they're gone.


This doesn't mean light it up like a soap opera - if you want dark and moody visuals that are a stop and a half under then light it to 2/3 of a stop under and crush that last 2/3 stop in post as opposed to underlighting on the chip.

Its up to you, the DP, to compress the contrast range to within the range of the uptake medium - be it film or video. That is one aspect of the DP's job description - regardless of medium.

Often the biggest problem on these boards is that people don't read posts before leaping in with their half cent worth.