Point me please to low light shooting theme

[Dmitriy84759]

Hi friends!
Tried to find it but no result. Could you point me where I can read about low light shooting with Magic lantern? Every time when I'm shooting frames with lack of light there is huge amount of awful color noise in dark areas. When I try to shoot something in crop_rec4k mode amount of noise increasing to the maximum level.
Help me please, I take a part in some amateur movie shooting, and soon will must shoot some dark scenes

[Bender@arsch]

Maybe some more information can help us: Camera, settings, ML Version...

[Walter Schulz]

Hi friends!
Tried to find it but no result. Could you point me where I can read about low light shooting with Magic lantern? Every time when I'm shooting frames with lack of light there is huge amount of awful color noise in dark areas. When I try to shoot something in crop_rec4k mode amount of noise increasing to the maximum level.
Help me please, I take a part in some amateur movie shooting, and soon will must shoot some dark scenes

Sorry but what do you expect? We all (should) know that high ISO will get you a lot of noise induced artifacts and pushing in post will get it worse. And Canon's sensor technology is not the greatest when it comes to low light shooting.
You have to do noise reduction in post if you are unable to add light to the scene.
ML cannot magically change sensor's abilities or lack of.

[yokashin]

eos m, iso 800
I set the lighting parameters for the brightest elements of the scene. The scene was illuminated by only two spotlights. In MLVApp I just brightened up a little. I did not remove the noise grain.

[garry23]

As a simple photographer, ie not a videographer, all I would say is try and maximise your photon capture by not over using ISO.

High ISO shooting doesn’t increase noise like many think, it decreases the signal to noise of the image, especially in the shadow areas.

You need to look for capture strategies that capture the most photons and know when your sensor becomes ISO invariant. ETTR at the low ISOs, ie below the ISO invariance point, but not at high ISOs.

On my 5D3, I would not capture above ISO 1600-3200. On M I personally wouldn’t shoot above ISO 1600.

As I say, I’m not a video person, but I would expect the same principles to apply, assuming you are post processing each RAW video frame. That is RAW video is ‘just’ RAW photography done repetitively 

[Skinny]

as a disclaimer - all I say below may not be technically right or correct.
but...

I found that overexposing a lot, somewhat helps in low-light situations.
For example, your scene looks correctly exposed at iso 400. Change it iso 1600, and you will get some highlights clipped and wrong exposure, but in post you will bring down the exposure -2 stops. Also the noise. It becomes a lot less visible... But try it at your own risk

Also, color noise is mostly red, so you can desaturate deep reds, and try to use less contrast and less saturation for night scenes overall, it will make noise less noticeable.
Try darkframe subtraction, maybe it will help too...

And record in 12 or 14 bits, 10 bits could be too noisy.

what else... you know the rule shutter speed should be 180 degrees, but if there is not much movement in a scene, you can use exposure override and set the exposure to 1/25 seconds (while filming at 24 fps), it is almost 360 degree shutter, but it is +1 stop more light. But watch for the lights flicker (60hz or 50hz frequency).

And remember that noise is really visible in the dark areas, so if your scene looking well-lit, then high iso is OK. But you don't have much room to maneuver in darker scenes. So you can just leave them dark as part of the style..
Anyway, you don't want to turn night into day with these not so suitable for night shooting cameras.. you have to keep all these things in mind when shooting in low-light.

[masc]

Did you try darkframe subtraction? You can eliminate all static sensor noise with that. It is very easy to do in MLVApp. https://github.com/ilia3101/MLV-App/wiki#darkframe-subtraction

[ArcziPL]

My loose thoughts (but I don't have much experience in low-light video, I'm definitely avoiding it...):
- don't increase brightness in post, i.e. expose well to the right, leave dark areas dark
- even if you have low-light conditions, use light sources of daylight color temperature (~5500K) or accept a yellowish look of your video. You'll get a lot of noise by using warm light and adjusting white-balance in post (because it will mean increasing brightness of a very noisy blue channel and also under-exposing the most important green channel).

[Levas]

If I'm correct topicstarter has a 5d3.

For best results in lowlight, you want to gather as much light as you can so:
Make shutter speed as low as possible, probably 1/33th of a second.
Shoot with the lens wide open(max aperture), the lower the F-number the better, depends on the lens, but probably F 3.5 or lower.
(Consider buying a lens with a big aperture, for example Canon 35mm I.S. F2.0)
As stupid as it sounds, but if you need it, don't be afraid to use high iso numbers like 3200 or 6400 (6400 max)
When in low light situations, you're better of with a right epxosure with iso 6400, then with a wrong exposure at iso 800 and then have to bump exposure in post proces.

Other things that help, shoot in normal pixelbinning mode, 1920x1080.
4K options are nice, but it's much noisieer because there is no pixelbinning done.
Pixelbinning helps in reducing noise, especially on the 5d3 which bins both horizontal and vertical.

So
Shutter speed of 1/33th seconds
Wide open aperture (lowest F number)
High iso, like 3200-6400
1920x1080 in pixelbinning normal mode

And there is one other thing which helps a lot on the 6d, probably also on the 5d3, but it's not in the standard builds.
But since crop_rec 4k recording options became available, ML switched from rawtype stream 0x12 to 0x10.
Rawtype 0x12 doesn't work in altered crop modes.(only in vanilla crop modes when 5x zoom is used without crop_rec module)

Rawtype 0x12 is much cleaner (at least on the 6d that is, but my guess it's also the case for other cams).
With rawtype 0x10, you will see vertical lines(vertical bands) when using high iso on low light scenes, when rawtype 0x12 is used, these vertical banding is gone.
My guess is that Rawtype 0x12 is the cleanest rawtype where Canon performs some sort of darkframesubstraction in camera.

In the source code of magiclantern you can find "raw.c" in the "src" directory.
In raw.c you can find this line

Code: [Select]

#undef RAW_DEBUG_TYPE   /* this lets you select the raw type (for PREFERRED_RAW_TYPE) from menu */

change the "#undef" to "#define" and compile a build.

Code: [Select]

#define RAW_DEBUG_TYPE   /* this lets you select the raw type (for PREFERRED_RAW_TYPE) from menu */

When doing this you get an option in the debug menu to change rawtype to whatever you want, default is 0x10, but if you set it to 0x12 and record high iso, like 6400, you still get pretty good results.

[Danne]

You should be able and hard code your rawtype in raw.c:

Code: [Select]

#ifdef CONFIG_DIGIC_V
#define RAW_TYPE_REGISTER 0xC0F37014
#define PREFERRED_RAW_TYPE 0x10         /* CCD; also valid for DIGIC 6 */
#else
#define RAW_TYPE_REGISTER 0xC0F08114    /* PACK32_ISEL */
#define PREFERRED_RAW_TYPE 0x5          /* DIGIC 4: CCD */
#endif
But there have been many attempts for both eos m and 5D3 to find a better rawtype. Conclusion was to stick with that we have.

[Levas]

No doubt rawtype 0x10 is in most scenarios the best.

Without rawtype 0x10, there is no crop_rec module. Couldn’t live without it   
It also gives about half a stop more dynamic range compared to 0x12 (which suggest some sort of darkframesubstraction)

But there is one field where 0x12 is the better option and that is lowlight in combination with high iso (3200-6400).

It’s an interesting niche option for very few scenarios. But it’s good to know it exist.

[Danne]

All testing here is most welcome. On 5d3 there was a stream giving plenty colored dots instead of vertical stripes. At least less stripes. Think the general conclusion back then was to stick with 0x10.