Preparing for music video - Noise at high ISO

Started by MartijnR, June 03, 2014, 12:15:47 PM

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MartijnR

Hi,

I will soon start shooting a music video, and have a technical question. Some help is much appreciated.

- When shooting RAW on my Mark III, I get a lot of noise when my ISO is above 1250 in a dimly lit room. Is this normal? Sometimes I see videos with very high ISOs without any noise. The music video will take place in a dimly lit room. Is there a setting to decrease this noise?

Thanks!

Martijn

[email protected]
www.zerolandscape.com   

a1ex

Quote from: MartijnR on June 03, 2014, 12:15:47 PM
Is there a setting to decrease this noise?

Aperture and shutter speed. Try to capture as as many photons as you can (even if this forces you to darken the image a little in post).

FYI, there are no intermediate ISOs in video RAW; older builds had some display bugs.

MartijnR

Thanks a1ex for your quick reply, much appreciated!

Midphase

On the 5D3 anything below 1600 should be pretty damn clean. Are you sure your sensor isn't overheated?

kihlbahkt

QuoteWhen shooting RAW on my Mark III, I get a lot of noise when my ISO is above 1250 in a dimly lit room. Is this normal? Sometimes I see videos with very high ISOs without any noise. The music video will take place in a dimly lit room. Is there a setting to decrease this noise?

Post processing with denoiser either with the tools in After Effects or use a 3rd party denoiser like Neat Video can make significant improvements in visual noise. As stated by a1ex get light in there to reduce noise during shooting.
600D x2

Midphase

Also, are you ETTRing? Underexposure will likely result in an image with artifacts in the mids and shadows...not necessarily noise but it can be commonly mistaken for noise.

For all intents and purposes, an underexposed image at a lower ISO will result in considerably noisier-appearing video than a slightly overexposed image at higher ISO that's been clamped down in post.

a1ex

Quote from: Midphase on June 03, 2014, 08:30:29 PM
with artifacts in the mids and shadows...not necessarily noise but it can be commonly mistaken for noise.

Have an example of such artifacts?

Midphase

Just muddy looking shit. You know the deal...less bits assigned to the shadows. Why else shoot in ETTR then?

a1ex

Quote from: a1ex on June 03, 2014, 08:50:13 PM
Have an example of such artifacts?

An image (DNG+JPG), if this was not clear.

MartijnR

Hi Midphase and kihlbahkt,

Thanks for your replies! Yes, I use denoising in After Effects. It can help, but it can become too smudgy when there is a lot of noise.

Regarding ETTR, I don't use it, considering in a dimly lit room the autoETTR quickly goes to ISO 6400, and I assume this will lead to a lot of noise. However, if I understand the theory correctly, ETTR should reduce noise. I might give it another try.

I usually try to keep the ISO under 1000 in dark situations.

I have been thinking about using Dual ISO, but my first tests contain too much aliasing (and some artefacts). So, I will probably choose for normal RAW.

Midphase

I think people misunderstand ETTR.

What ETTR means is not necessarily to use the auto-mode, but rather to get an exposure which might seem a tad bright for your end purpose, but which contains better data in the image.

Some DP's prefer to shoot as they want the final product to look, so if they prefer a darker overall image, they will underexpose. When shooting raw, this is a mistake. It's best to push the exposure, and then tone it down in post.

ETTR simply means push your exposure as high as it will go without blowing out your highlights.

MartijnR


Midphase

FWIW, I've shot acceptable looking footage at 3200 ISO on my 5D3. Granted noise acceptability can be a bit of a subjective thing, but I feel that even 1600 ISO can provide a rather clean video image.

You should be able to push well past 1000 ISO without running into anything that looks overly noisy. However if the sensor is overheated, that can actually add noise to the image regardless of the ISO.

MartijnR

Thanks! Maybe a stupid question, but are there certain precautions you can take to prevent sensor overheating?

redaber

Quote from: MartijnR on June 04, 2014, 12:16:59 AM
Thanks! Maybe a stupid question, but are there certain precautions you can take to prevent sensor overheating?

wait, is this a temporary thing? how do you know if you overheated your sensor?

kihlbahkt

The sensor and camera will heat up with use. An "Overheated" sensor will increase noise in the recorded image/video. It is a temporary situation. I don't have any details about this subject only what i have read. I personally have never noticed this in my video but the camera does not stay on very long for most of my shoots. 
600D x2

Audionut

Quote from: MartijnR on June 03, 2014, 09:28:51 PM
Regarding ETTR, I don't use it, considering in a dimly lit room the autoETTR quickly goes to ISO 6400, and I assume this will lead to a lot of noise. However, if I understand the theory correctly, ETTR should reduce noise. I might give it another try.

I have been thinking about using Dual ISO, but my first tests contain too much aliasing (and some artefacts). So, I will probably choose for normal RAW.

Higher ISOs are less noisy then lower ISOs.  In dimly lit rooms, ISO noise is not the problem per se, shot noise is going to be the major determining factor.  And you can only control shot noise with exposure (shutter/aperture). 

Think about your light source.  You may consider using a stronger light source to capture the scene, and creating the impression of a dimly lit room in post.

Dual ISO is only really useful in scenes with large dynamic range, and where you can use a low ISO.  A dimly lit room probably doesn't satisfy those requirements.

kihlbahkt

Yes. The camera wont produce good images without light on the sensor. Light the scene in as creative a way as possible to keep the dim vibe real in post. Use contrasting dark and light areas of the scene and light it brighter than what you want as a final product and then begin to create that "dim room" in post. I think that lighting the scene well and as creatively as you can will be the best solution for reducing noise...maybe you can reduce ISO cuz you have more light. Keep your aperture as big as possible. Either way you have more light on the sensor. Your 5d3 video should look awesome if given enough light, and then post process for that church basement/ strip club look. Oh darnit....Now secretly wishing that when I go over to my bag I will find Canon elves have left me a 5d3 with a gift card for 10k$ of glass. Use as much light as you can to keep your sensor happy.
600D x2

MartijnR

Thanks for all the great advice! Much appreciated!

jimmyD30

FYI- In Canon user guide for 5DM2 it says high sensor temps will affect photos, but NOT videos, go figure. They do say if it gets too hot the camera will shut down in video mode, but no degradation in video quality will occur due to high temps alone. Doesn't make sense to me, maybe because video is only using a small portion of the sensor?

Either way, not sure if this Canon statement about high temps not affecting video applies only to native H264 or ML raw as well, any thoughts?

kihlbahkt

So I had to go look it up in my 600D manual. Says the same thing. Still images are impacted by a hot sensor but not video. There are two warning icons for heat. The first is a white icon and the second is a red icon. You should shut down cam if shooting stills and get the white icon warning. Video can be captured with a white warning icon. In either movie or still mode once the red icon warning is displayed that cam may shutdown by itself if the user does not shut it off. Obviously, Canon wrote this for h.264 and not raw.
600D x2

jimmyD30

Yes, Canon wrote the entire UG without regard to ML, but ML raw uses the same CMOS sensor as native H264, so why should it be any different?

Probably only ML devs can answer...

And in general, does anyone have any insight as to why high sensor temps would affect photos and not videos as per Canon UG?


MartijnR

Just to check if this is normal noise, I did a little test and have a dropbox-link (DNG and JPG) with ISO 1600 (3200 is actually not much different), f about 3 I think, shutterspeed 48.

https://www.dropbox.com/sh/5vfyxyaj042sffh/AAC3rJx1bE5jfQxedSXPb18Ba

I used RAWMagic Lite. I recently used the original RAWMagic but I suddenly had a lot of vertical noise lines. There still seems to be a bit of it.

Looking at the parfum box, there is quite a lot of noise. But please keep in mind that the room was quite dimly lit, so I assume the noise is normal.

There is no denoising, just straight out of the camera. Of course the noise is almost gone when doing some post-effects.

Thanks

a1ex

I had to brighten it in post by at least 3 EV. With this in mind, the noise levels are very good.

MartijnR

Great to hear! Thanks for letting me know, a1ex!