Noise and filming/ F stops and other

M

mrpink89

Does anybody know How I can reduce noise while filming night scenes for example like a sun rise or a sun set. or even a street lit up by street lights?

Everything i have seen is for DSLR this and DSLR that. Man does anybody own an actually video camera anymore?

Trying to find that sweet spot with my F stops but can't seem to. and while we're at it. what's an F stop any ways. I know what it does but I feel i should now why its called an F stop and what's the difference between an F stop and a ND.

My camera, when adjusting the aperture goes all the way from F stops to N/D what is ND?

I have heard that adjusting the shutter speed can help give a good clear of what I am trying to shoot, but i have also heard that i doesn't. Dude confused as all hell.

and a side question. When did the world become so obsessed with clear pictures? was it always like this? like even back in the 70s. I mean things were pretty grainy then. Now it seems the game has changed and its all about clear images and sharpens.

wow. this turned into a question/rant I apologize, any takers on this subject?
 
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Filming during nighttime?

Faster lenses and lighting. Depending on nearby outlets and power sources, you may have to get a generator (and extension cords if you will be recording audio). You put the generator as far away as you can from the area you are shooting in, then run an extension cord over to your light(s). That way the noise coming from the generator is not heard later with the dialogue. If you cannot put the generator far away, maybe it's a crowded or shady area, then you may have to do ADR later. If there is going to be no audio recording, have the generator where ever you want.

What's f-stop?

f-stop
noun PHOTOGRAPHY
noun: f-stop; plural noun: f-stops
1.
a camera setting corresponding to a particular f-number.
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What is an f number?

f-num·ber
nounPHOTOGRAPHY
1.
the ratio of the focal length of a camera lens to the diameter of the aperture being used for a particular shot (e.g., f8 , indicating that the focal length is eight times the diameter).
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What does that mean?

http://en.wikipedia.org/wiki/F-number

Aperture_diagram.svg


Diagram of decreasing apertures, that is, increasing f-numbers, in one-stop increments; each aperture has half the light gathering area of the previous one.

f/1.2 is a f-stop number. f/8 is another f-stop number. f/1.2 means the lens is open wider, meaning more light can be let in to hit the camera's sensor. That means brighter scenes.

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ND? Some cameras have ND filters built into them. What is an ND filter?

http://en.wikipedia.org/wiki/Neutral_density_filter

Shutter speed?

http://www.webopedia.com/TERM/S/shutter_speed.html

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Here's a video that may help you:

https://www.youtube.com/watch?v=kD8nXGt91yo
 
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ChimpPhobia said it. I agree though, about people wanting clear pictures. It seems that grain is okay if it's a big blockbuster movie, like Green Zone or a lot of older movies, but if it's a microbudget film, everyone wants clear picture, and it's becoming a double standard possibly. But I guess with a multimillion dollar movie, you can have a grain, and the company is still forced to release the movie even if they don't like the quality, cause of the signed contracts, and all the money spent.

As far as everyone owning DSLRs, I actually think that's a good thing, cause video cameras, without interchangeable lenses, can be a hassle with limitations from what I've seen.
 
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harmonica44 said:
ChimpPhobia said it. I agree though, about people wanting clear pictures. It seems that grain is okay if it's a big blockbuster movie, like Green Zone or a lot of older movies, but if it's a microbudget film, everyone wants clear picture, and it's becoming a double standard possibly. But I guess with a multimillion dollar movie, you can have a grain, and the company is still forced to release the movie even if they don't like the quality, cause of the signed contracts, and all the money spent.
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where are your sources...
 
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Thanks guys, haha film riot, awww yeah gotta love them and BFX. I'm gonna get a DSLR one day but it is a bit irritating because most videos and articles online only talk about DSLRs
 
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But as for noise Im talking about not shooting with audio, like photo noise you know. So If I am shooting a street lit up by nothing more than street lights and or neon signs how do I get a good shot without all the noise? I don't want to open the appature to much since that would give me noise, but i dont want to not let in enough because well, yeah that would give me noise also.

Camera i am using is a Canon vixa HF G20

Also when adjusting the aperture it starts at f1.8 which lets in a lot of light then decrees to "F4.0 ND 1/2" and so on so what does this mean
 
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mrpink89 said:
But as for noise Im talking about not shooting with audio, like photo noise you know. So If I am shooting a street lit up by nothing more than street lights and or neon signs how do I get a good shot without all the noise? I don't want to open the appature to much since that would give me noise, but i dont want to not let in enough because well, yeah that would give me noise also.
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I know you are not taking about audio. I am just saying that you should consider how you are going to record usable audio for a film if you use a generator for lighting equipment. If you light your scene, that gives you the chance to turn your ISO down, which means you will not get all of that ugly noise. But if you do not have a power outlet nearby, you may need to use a generator. You have to think ahead about how a decision in one department of a film will affect another.

Also, The aperture has no direct effect on signal to noise ratio. Turning your ISO up is what causes noise.
 
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got ya, follow up question. Why am I seeing some noise in some dark spots when the iso (gain) as my camera calls it. is not in use. i never touch the gain because i know it can give noise so im a bit confused as to why I am seeing noise on my footage. when the iso is not in use and I am just using the aperture.
 
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mrpink89 said:
got ya, follow up question. Why am I seeing some noise in some dark spots when the iso (gain) as my camera calls it. is not in use. i never touch the gain because i know it can give noise so im a bit confused as to why I am seeing noise on my footage. when the iso is not in use and I am just using the aperture.
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Noise is caused by turning the ISO up. But it's also caused by underexposure. The reason why it's noisy in the dark spots is because you are underexposed in those areas. But if your ISO is turned all the way down, as you make it sound when you say it's not in use, then you probably shouldn't have noise in those areas. Shooting at night though, you think you wouldn't be able to see anything at all with the ISO turned down that much.
 
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You seem to be under the impression that a DSLR has perfect, noiseless low-light performance.

Not even the highest quality film camera can record a perfectly noise/grainless image in extreme low light (like a single street light). And chances are they'd have the ISO turned up to at least 1600*, which would cause a little grain. But it would look totally fine, as long as they were shooting at a lower aperture.

Saying that you have the ISO "turned off" makes no sense, and implies you may need to learn a little bit more about the cameras before you try shooting in such extreme situations. You would HAVE to turn the ISO up past 100, even during the day sometimes. Yes it can produce more noise, but it also brightens your image and prevents underexposed-looking footage. Watch videos, read photography/videography tutorials (same technology, same properties, you can learn from both!), and remember to have fun while doing so!


*I realize that ISO for film is different. You have to actually buy film with the ISO you want (like, say, ISO 800 or ISO 1600) and can't set it in-camera. Yay for digital conveniences! :D
 
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Yodaman said:
You seem to be under the impression that a DSLR has perfect, noiseless low-light performance.

Not even the highest quality film camera can record a perfectly noise/grainless image in extreme low light (like a single street light). And chances are they'd have the ISO turned up to at least 1600*, which would cause a little grain. But it would look totally fine, as long as they were shooting at a lower aperture.

Saying that you have the ISO "turned off" makes no sense, and implies you may need to learn a little bit more about the cameras before you try shooting in such extreme situations. You would HAVE to turn the ISO up past 100, even during the day sometimes. Yes it can produce more noise, but it also brightens your image and prevents underexposed-looking footage. Watch videos, read photography/videography tutorials (same technology, same properties, you can learn from both!), and remember to have fun while doing so!


*I realize that ISO for film is different. You have to actually buy film with the ISO you want (like, say, ISO 800 or ISO 1600) and can't set it in-camera. Yay for digital conveniences! :D
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just as a note, multi ISO's like 160 is cleaner than ISO 100.
 
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Chimp's covered F-stops and NDs.

You're using a traditional camcorder, which is a little bit more confusing than DSLRs when it comes to this intermediate exposure stuff - at least intermediate for the camera you're using.

Gain = bad. Gain is not quite the same as ISO, though it has a similar effect when you start using it. Camcorders generally have a base ISO that's not really published, and often doesn't matter as 99 times out of 100 when using such cameras, you're not using a light meter to set lights, and are instead using Zebras, along with your Waveform monitor.

The base ISO of such cameras is generally quite slow, at least in comparison to current digital cine cameras (I know the EX3 used to generally be rated at ~320 ISO at 0db of gain). Adding or subtracting gain is basically the same thing as raising or lowering the ISO, but of course you can generally set the amount of steps you go up in (i.e. +3 or +6db as Medium or High, depending on how you like(d) to work).

The take-away is that Gain is essentially the same as ISO, but it works slightly differently and is a lot more confusing than cameras that simply give you a standard ISO readout.

The more you open up your lens (i.e the smaller the number), the more light you can let in, and the less gain you will need to use to have an image. This is good.
Noise can also be present in dark or underexposed areas, partly because of the compression algorithms and bit-depth of cheaper cameras.

Camcorders typically have a much smaller dynamic range than any film stock or digital cinema camera. Therefore, you would traditionally light within the dynamic range to get you the best looking footage, eliminating noise etc.
This would mean that your contrast ratios are suddenly a lot less contrasty, at least compared to film, and your naked eye. Whereas in film or on say, an Alexa, you might have 14 stops of latitude, in traditional digital camcorders, you might have 3-5 useable stops of latitude - this basically means you have to really light camcorder footage for it to look good, and especially for it to be clean and noiseless.

On the topic of clean vs 'noisy':

Many films have been shot grainy. There's grain over every motion picture that's shot on film, whether it's really fine grain or really obvious grain, it's there. Film grain, however, is very different looking to digital noise. The reason heavier grain appears is the same as digital noise.
Film grain, however, seems to be regarded as 'nicer' and more 'organic' looking.

See for yourself (from Wikipedia):

Film grain:
800px-MartinIversenNorway1991.jpg


Digital Noise:
Highimgnoise.jpg



Apart from the softness and compression in the digital image, the noise is colourful, and overall pretty ugly, whereas the film grain is at least somewhat pleasing to the eye and aesthetic.

8salacious9 said:
just as a note, multi ISO's like 160 is cleaner than ISO 100.
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This is true only of Canon DSLRs.
 
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harmonica44 said:
Noise is caused by turning the ISO up. But it's also caused by underexposure. The reason why it's noisy in the dark spots is because you are underexposed in those areas. But if your ISO is turned all the way down, as you make it sound when you say it's not in use, then you probably shouldn't have noise in those areas. Shooting at night though, you think you wouldn't be able to see anything at all with the ISO turned down that much.
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Harmonica, I don't understand this statement seems a little bit contradictory. your saying the footage is noisy because its underexposed. But you're also saying i shouldn't be seeing any noise at all. Kinda confused.
 
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No, what he's saying is that you shouldn't be able to see ANYTHING at night with such a ridiculously low ISO. It's true that you can have noise from under-exposing, too. Even though you're shooting at a low ISO (which yes, theoretically should give you reduced grain), you NEED light in your scene to actually remove the grain, as well as a wider aperture. I posted about it in your duplicate thread, so check there for my detailed response.

Really shouldn't have two threads about the very same subject... plenty of good info in this thread, didn't need to start the second.
 
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