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-   -   Solutions for dealing with noise and grain in low-light shots? (https://www.dvinfo.net/forum/canon-vixia-series-avchd-hdv-camcorders/109394-solutions-dealing-noise-grain-low-light-shots.html)

Paul Tauger December 3rd, 2007 02:25 AM

Solutions for dealing with noise and grain in low-light shots?
 
I've returned from a trip with a lot of night shots. They looked fine on the built-in LCD but, as I edit them, it's obvious that there is a lot of noise and grain, no doubt from the camera's gain getting kicked up.

Two questions:

1. How do I avoid this in the future? I shot at 1080i/60 and would prefer to avoid the issues of shooting at 24p, though I would if there is no choice. Does the camera's "cine" gamma setting defeat the gain? It's not practical for me to try to lock the aperture off for each shot.

2. Any good post solutions? I've seen some filters ranging from free for a Virtual Dub plug-in to a couple of hundred dollars for a Premiere Pro plug-in. I'll spend the money if I have to, but not on something that offers only marginal benefits.

Seun Osewa December 3rd, 2007 02:38 AM

1) Add light. Cost: < $500
2) Get a more sensitive camera. Cost: $5000+
3) Clean it with Neat Video. Cost: < $100

Tom Hardwick December 3rd, 2007 02:43 AM

I invariably do some exterior night shots of the wedding venues I film, and shooting at a very slow shutter speed on the Z1 (on a solid surface of course) means I can have no gain-up at all. Remember that correcting exposures in post never looks as good as getting it right up front.

Of course if you need to film natural movement you'll simply have to add more light - there's no two ways about it. You can't 'defeat the gain' if you amplify the signal electronically, though I'm pretty pleased with the way the Z1 trades grain for sharpness in 1080i, it a fair swap in my view.

I'm slighty horrified to learn you don't lock down the exposure for each shot Paul. It really is the number one requirement in any movie scene.

tom.

Steve Brady December 3rd, 2007 05:13 AM

I use the UK version of the camera, so there may be some difference in behaviour, and obviously the PF25 mode doesn't have the pulldown problems that the 24p mode has, but overall -

When you use the PF25 mode in combination with Cine mode, the camera will try and keep the shutter at 1/50, but if it needs to increase exposure, it'll drop the shutter to 1/25 before it bumps up the gain. Overall, as long as you don't swing the camera around too much, this gives a fairly nice motion signature.

Quote:

Originally Posted by Tom Hardwick (Post 786254)
I'm slighty horrified to learn you don't lock down the exposure for each shot Paul. It really is the number one requirement in any movie scene.

Obviously, that's the ideal, but sometimes, it's not an option. Overall, I like the way that the HV20's auto exposure works - if you have to transition from interior to exterior, for example, the auto exposure rate change is fairly pleasant and natural, but, like most consumer camcorders, the HV20 tends to expose a bit hotter than I'd like it to. If I could change just one thing about the camera, I think I'd like it to have an EV function in place of - or, better yet, in addition to - the Exposure Lock function.

Paul Tauger December 3rd, 2007 11:15 AM

Quote:

Originally Posted by Seun Osewa (Post 786250)
1) 3) Clean it with Neat Video. Cost: < $100

Have you (or anyone else) tried Neat Video? The demo of the filter is useless as it's limited to VCD/VGA frame sizes and won't allow a test on HDV material. $99 isn't that much, but I don't want to throw it away if Neat Video is useless.

Quote:

Originally Posted by Tom Hardwick (Post 786254)
I invariably do some exterior night shots of the wedding venues I film, and shooting at a very slow shutter speed on the Z1 (on a solid surface of course) means I can have no gain-up at all. Remember that correcting exposures in post never looks as good as getting it right up front.

Of course if you need to film natural movement you'll simply have to add more light - there's no two ways about it. You can't 'defeat the gain' if you amplify the signal electronically, though I'm pretty pleased with the way the Z1 trades grain for sharpness in 1080i, it a fair swap in my view.

I would take an under-exposed image over one with the gain kicked up. My VX2000 was spectacular in low-light, giving virtually noiseless images by candlelight. I didn't expect the same performance from the HV-20, but I'm a bit disappointed with just how noisy the image is.

Quote:

I'm slighty horrified to learn you don't lock down the exposure for each shot Paul. It really is the number one requirement in any movie scene.

tom.
I shoot travel video which means, (1) it's run-and-gun most of the time which doesn't permit either locking down exposure or adding light, and (2) I have absolutely no control whatsoever over lighting conditions. Adding light, as a previous poster mentioned, isn't an option. I used to carry a small outboard light when I shot with my VX2000 (it was powered off the same type of batteries as the camera, so it was easy to use). I wound up using it only once, in some caves in northern Spain. For the kind of stuff I do, however, a single auxiliary light wouldn't help at all -- it would just give that "home movies" lit-from-the-front-by-too-bright-a-light look. Obviously, properly lighting a scene isn't an option.

Jim Montgomery December 3rd, 2007 11:23 AM

Paul, et al

I just tried the Neat product on some EX footage 1080p24. It was incredible, I was awe struck by the easy, simplicity, and outstanding results.

Jim

Paul Tauger December 3rd, 2007 11:34 AM

Quote:

Originally Posted by Jim Montgomery (Post 786475)
Paul, et al

I just tried the Neat product on some EX footage 1080p24. It was incredible, I was awe struck by the easy, simplicity, and outstanding results.

Jim

Thanks, Jim. I'm going to get it today.

Paul Tauger December 4th, 2007 12:59 PM

Follow-up
 
I tried the Neat filter last night. Though not a perfect solution, it did a reasonable job of bringing the grain and noise down to something I'm willing to live with. One note, however: it adds, dramatically, to render times in Premiere Pro CS3.

Ger Griffin December 4th, 2007 03:11 PM

perhaps im a bit late on this.
I haven't tried neat, but exporting adobe media encoder you can turn on
noise reduction. Then use the clip again in the timeline.

It gives the footage a very nice look too.

David Delaney December 4th, 2007 03:13 PM

Paul have you tried the trick with mini-SD card and covering up the lens while setting the exposure?

Paul Tauger December 4th, 2007 03:33 PM

Quote:

Originally Posted by Ger Griffin (Post 787182)
perhaps im a bit late on this.
I haven't tried neat, but exporting adobe media encoder you can turn on
noise reduction. Then use the clip again in the timeline.

It gives the footage a very nice look too.

Oooops. A little earlier and you might have saved me $100. ;)

Quote:

Originally Posted by David Delaney (Post 787183)
Paul have you tried the trick with mini-SD card and covering up the lens while setting the exposure?

I haven't. Because I shoot travel video, I don't have time to do that for each shot -- it's strictly run-and-gun. The best solution would be either a hack or (better still) a firmware update that lets me disable gain.

BTW, do I assume correctly that, even if I select aperture priority and manually set aperture, the camera will still kick up the gain?

Chris Harris December 4th, 2007 03:37 PM

I would try the Cine mode as well. In most low light situations, I can't stand the gain, but Cine mode severely limits (or stops completely) the gain applied to the image.

Paul Tauger December 4th, 2007 03:40 PM

Quote:

Originally Posted by Chris Harris (Post 787196)
I would try the Cine mode as well. In most low light situations, I can't stand the gain, but Cine mode severely limits (or stops completely) the gain applied to the image.

That's interesting. When I was considering buying the HV-20, I looked at some sample footage posted at the Canon site. It included some very low-light stuff that was shot inside a bar -- it was smooth as silk, no grain and nice saturated color. Supposedly, it was demonstrating the difference between 60i and 24p. However, now that I think of it, it also had "cine" mode turned on for, I think, both clips. Perhaps all that's necessary to turn off gain is to turn on "cine" mode. It seems to me that, for night shooting, the flatter gamma of "cine" wouldn't necessarily be a bad thing, either. I'll have to give it a try.

Steve Brady December 4th, 2007 03:55 PM

See my post above. It isn't that Cine mode disables the gain, it's that it drops the shutter speed down to 1/24 before it applies gain. The gamma is just one aspect of the Cine mode.

David Delaney December 4th, 2007 09:09 PM

I am just learning, but I think you can just cover the lens (black) and set the exposure to get rid of the gain. Check with the mini-SD card to be sure if the gain is off or on?

http://www.dvxuser.com/jason/hv20/


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