General Darker areas seem much more noisy

K

kevinkt

Active member
So in my video, there are some areas that there are no light in, and that was purposeful. These areas have a ton of noise/gain and look like they're "flickering." Is there a reason I am getting these areas of high flicker/noise even though my ISO is very low?

And anything I can do in post to get rid of these?
 
First, stop being an asshat, second, stop being wrong.

Kevin, do you still have highlight tone priority on? If so, I would turn it off and see if it helps get rid of that noise, there shouldnt be noise in the shadows if you're shooting at 400 or below
 
randomname said:
First, stop being an asshat, second, stop being wrong.

Kevin, do you still have highlight tone priority on? If so, I would turn it off and see if it helps get rid of that noise, there shouldnt be noise in the shadows if you're shooting at 400 or below
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You have absolutely zero clue what you are talking about and you are about to send this guy on a wild goose chase.

1. HTP isn't going to help him *IN POST* which is what he asked.
2. Even while shooting, turning off HTP isn't going to help in unlit areas.
3. ISO has ZERO to do with noise in under-lit areas. It will only affect areas that are properly lit. Properly lit at ISO 100, is different than properly lit at 800 ISO.
4. The ONLY way he is going to get noise-free blacks is to light the dark areas to a base level that eliminates the noise on the sensor, and then light the bright areas at a desired contrast ratio that is within range of the sensor. Alternately, he can simply crush the blacks in post, but that may not give the desired effect if he wants to keep shadow detail.

So before you go calling people names, learn your facts.
 
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While I have gotten some pretty shocking results, mostly in forest tests or shadows, I honestly have come to realize that these things probably would rarely appear if I actually shot videos in professional situations. For instance, I shot some videos in a small super market where I plan on making a music video (as the lighting really turns out so beautiful in this particular store), and they truly looked outstanding, very minimal noise, very pretty colors, only minimal issues with detail and other types of realism problems. Shot some fruit in one video, bit of noise in this dark part of the shelf, but it honestly looked just the same from what I've seen in Red files.

Overall, and I think this is also just something I'm good at, but you really have to almost have an ingrained perspective over what will end up giving you a equal look on screen, and what won't. I personally have fussed and fumed over "worst-case scenario" tests, but to be honest, as I explore things that reflect more of my cinematic visions when it comes to producing a story, and shooting in the specific locations I usually think up, I realize that these cameras truly record great looking things if they are recording scenes that honestly do, even naturally, follow some specific cinematic rules.

For instance I once did a close-up of a tree in the style of a shot that I want in this very same production, just as a test. The specific tree I chose for this test turned out beautifully itself, but the location had it's background in the forest going down deep into a dark valley; result was, the most horrible noise I'd ever seen under ISO 800 happened in the valley background. But for the scene I imagined in my story from the beginning, I wanted the land to be completely flat and level, equal light distribution through the background forest. Just so happened this specific type shot would have probably produced excellent results instead. As writers, most people tend to naturally think of the most cinematic things naturally, unless they are purposely trying for a unprofessional camcorder look, so I'd say truly try to keep true to your own visions and if you're dedicated to a run-and-gun style, which tends to produce a mixture between camcorder and professional looks (documentary-esque), it still calls for shooting in places that truly are very well lit, or are at least very even.

Again, like in my supermarket tests, I think I had just one shot I was unsatisfied with the noise in a area of dark shadow or some mess. Ends up, it was a shot that I'd have never have shot for the music video I want to do in that store to begin with. Everything else, shots that I naturally shot somewhat alike to what I envision in the video, they all turned out noise free. Artistic vision seems to, subliminally, set itself up according to the rules we see in films every day. But so far, there's many types of shots I'm thinking of for future projects that scare me to death on how I'm possibly going to do them, so I don't think this honestly can be applied everywhere. Just, to be honest, I've only gotten awful results from the T2i when I purposely wanted to test worst-case-scenario type stuff, everything else has honestly looked pretty darn good.

That's just concerning noise though, I do have to say my current problem is trying to make my videos have more detail and depth; that very well could be one thing that better lighting would make much, much better, although I feel like it would be more of an illusion than actual detail repair. But everything helps, just, everything is also expensive.
 
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PerroneFord said:
You have absolutely zero clue what you are talking about and you are about to send this guy on a wild goose chase.

1. HTP isn't going to help him *IN POST* which is what he asked.
2. Even while shooting, turning off HTP isn't going to help in unlit areas.
3. ISO has ZERO to do with noise in under-lit areas. It will only affect areas that are properly lit. Properly lit at ISO 100, is different than properly lit at 800 ISO.
4. The ONLY way he is going to get noise-free blacks is to light the dark areas to a base level that eliminates the noise on the sensor, and then light the bright areas at a desired contrast ratio that is within range of the sensor. Alternately, he can simply crush the blacks in post, but that may not give the desired effect if he wants to keep shadow detail.

So before you go calling people names, learn your facts.
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This is just the 100% truth. Even your dark areas must have some kind of lighting to avoid noise. Personally a little noise is not that bad for me, but if you want a super clean image you need proper lighting. It's just the way things work.
 
In addition to lighting considerations, it's certainly worth checking that HTP, ALO and PIC are all turned off, as they can exacerbate shadow noise.
 
ISO effects noise. That's digital grain. Happens in film too. Lower ISO = cleaner image. With that said though there will always be a bit of noise in the image but with better settings you can reduce this.

There is a thread specifically that someone did (might be Barry Green) showing how much noise (grain) you get with different ISO settings.

Lastly you might add noise on other things such as:
1) when you transcode
2) when you push color correction and color timing too far
3) on output encode

Look all over the web and this forum and you'll see people have shot with high contrast images and still can acquire a clean enough look.
 
kevinkt said:
So in my video, there are some areas that there are no light in, and that was purposeful. These areas have a ton of noise/gain and look like they're "flickering." Is there a reason I am getting these areas of high flicker/noise even though my ISO is very low?

And anything I can do in post to get rid of these?
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Another good reason for lighting your blacks/shadows is that camera sensors have far more tones available in the lighter side of the range than the darker. If you don't feed any light to the shadows, they get crushed, and boosting them in post will only give you noise. If you do light your shadows, in post you can darken them and increase the contrast of the image to achieve noiseless blacks.

This is partly why it is better to overexpose by 1/2-1 stops - not blow out - than underexpose.
 
What have people experienced with dark areas that can't be lighted, for example the dark night behind a properly lighted subject on the street?
I know that sometimes it's feasible to light the background, or light some smoke or steam, but what about a dark night sky or unlighted area?
 
filmtovideo said:
What have people experienced with dark areas that can't be lighted, for example the dark night behind a properly lighted subject on the street?
I know that sometimes it's feasible to light the background, or light some smoke or steam, but what about a dark night sky or unlighted area?
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No light = same issue. There's no free ride here. This is partly why producing feature films is expensive. EVERYTHING has to be lit. Even if it has to be lit with large light sources placed on a crane. That bank of $75k lights hoisted by a $3k per day crane, has to be there, because the camera needs light. What you make it look like in post is another matter entirely.

I recently shot a "basement" scene that was supposed to look like it was lit by a single incandescent bulb. I didn't have a ton of light down there, but I had enough so that it was easy for the actors to check scripts, and for the script sup to work, etc. In post, I dropped the light by 4 stops in most areas so that it really DID look as though there was only one dim bulb lighting the scene.

As Shot:

38392_431191477896_511227896_4857980_1786964_n.jpg



Director's intent:


38212_431191462896_511227896_4857979_7704588_n.jpg
 
It's not a perfectly noise free sample, as we were shooting a 5D at 640 ISO due to REAL lighting (or more correctly power) considerations, but it's a reasonable example. Had I shot the scene to the darkness of the directors intent, it would have been a noisy mess regardless of selected ISO.
 
I get what you did but it looks all that great. There is a way to it where the contrast doesn't fall off naturally. The image looks exactly like the method you used which is light it more then darken in post. The guy in the background has a weird level of light on him after the adjustment has been done. Doesn't look very natural. It actually seems like there should be a bit more light on the man sitting away in the corner.
 
draven4 said:
I get what you did but it looks all that great. There is a way to it where the contrast doesn't fall off naturally. The image looks exactly like the method you used which is light it more then darken in post. The guy in the background has a weird level of light on him after the adjustment has been done. Doesn't look very natural. It actually seems like there should be a bit more light on the man sitting away in the corner.
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Yep. I told the director he was defying the laws of physics asking for it to be graded this way. He said this is the way he wanted it. Though this is not a finished grade, it is what he wants. It's his production and his money. So there ya go.
 
Perrone, did you do some masking on the machinery behind the seated guy? The level of highlight on the metal rim was significantly lowered.
 
For the sake of understanding this scene my directives were:

1. Dark basement lit by single light source.
2. Two shadowy figures. Seated figure should "appear out of the dark" in the opening scene, and just barely be visible for the remainder of the scene.
3. Make erase the wall behind the seated figure making the space appear larger than what we really had.
4. We had one prime lens (a 50mm 1.8). And the fastest zoom was an F3.5. The 50 was unusable since we were on a FF system
5. I had a total of two 120v plugs available for lighting. Period. And no generator.
6. There was no A/C, it was August, and it was 110F in the building. So no hot lights.

Without question, this was the hardest shoot I'd ever been on, as I knew we'd have to completely relight the set in post. My goal was to simply get a usable image in the camera.
 
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