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Old January 7th, 2006, 02:48 PM   #1
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Noise vs. Grain

So ive just been wondering. Is there any difference between the two. Ive heard some people say the DVX has alot of "noise" and some people say "gain". That just an example, but I honestly don't get it.
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Old January 7th, 2006, 04:33 PM   #2
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They are related, but not the same. Gain is a camera's setting that, for lack of a better analogy, turns up the "volume" on the CCDs so that dim images can be seen. The problem with this is that dim signals aren't very strong, so you get the equivalent of "static" coming through. What this looks like is a bunch of random pixels flashing throughout the image. Also, color is usually faded. Most cameras have gain settings that go way too far into the noisy range. My camera, the VX2000, goes up to 18db of gain but anything above 12db looks bad. Even 12db of gain causes some noise, but it allows me to shoot in dimly lit rooms.

If you can control the light situation, you can avoid using gain. Just bring the lights up enough that you have sufficient exposure. One thing to be cautios of is automatic gain settings. If the camera is fighting your iris settings by adding gain, it will make your image look bad. Make sure automatic gain is turned off. You really want to be in control of this setting as it can make your images look bad, even in good light.

Edit: I just realised that you used two different words in your post to describe the situation. "Grain" and "gain" are two different things. "Grain" in video images is the same as "noise". Grainy images in film is a somewhat similar effect caused by the grains (granules) of chemicals that make up the film. "Gain" is the camera setting that causes "gRain" in a video image.
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Old January 7th, 2006, 04:58 PM   #3
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haha, thanks. but that totally wasnt what i was asking. It was in reference to Grain and Noise.
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Old January 7th, 2006, 05:19 PM   #4
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Noise is like the grain on film, but the video-version.
And grain... well, is noise, but on film.

Grain looks better then noise, though.
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Old January 7th, 2006, 06:04 PM   #5
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GRAIN is a film term, relating to the actual "Grains" of silver halide (and other chemicals) present in the film. The larger the 'grains' the faster the film... meaning it will absorb light faster... meaning it can be shot in 'low light levels'. So - a 'fast' film has large 'grains' and can be shot at low light levels, with the trade off that the 'grains' are actually more visible in the image, especially the larger the image is printed/projected.

Video does not have "GRAIN" in the technical sense. Though there are some software programs and filters and such that can 'simulate' the look of grain, it simply doesn't exist in video.

When shooting at low light with video, you can turn up the 'gain' on the ccd's. As pointed out, this will boost the signal, and all the 'noise' that goes with it. The video "Noise" from increased gain will show up as tiny spots of flickering light, much like static, most easily seen against dark backgrounds.

So, it's understandable that you might confuse the terms 'grain' with 'gain' , and "noise" as both are important concepts when it comes to shooting in low light. I will add this though, while the noise added to video from increased GAIN is almost always a distraction, the look of increased GRAIN in film can be an aesthetic choice. Grain is not made up of white flecks in the film, but of 'granulated' colors/shades that lend a certain organic look that we have come to accept, and even expect from film images. One might even readily CHOOSE an exceptionally grainy film stock for a particular film look.

Hope this clears it up.
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