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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Getting noisy footage at 200fps

Kurt Naeslund

Kurt Naeslund

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Hello,

Yeah, I am a newbie, but I hope someone can help anyways.
I just recently did a few outdoors shots with our RED Dragon, in 2K and 200fps. Lots of daylight and using Canon L-lenses.

I delivered it through Davinci Resolve.

It seems like the footage has got so much noise? I did try to denoise footage in Resolve as well, but without any luck.

https://vimeo.com/147883385

All help is appreaciated

Regards,
Kurt
 
Hey thanks Eric,

Thats a good point. I will do more tests, to see if I can find a nice config. If you have any other advice, please let me know!

Thanks,
Kurt
 
Kurt,

I'm going to go through a few basic things.

1. 2k footage is a center cut of the sensor. This means that you are not scaling the footage from the whole sensor but only cutting out the center.

2. Shoot aa the lowest compression ratio possible when shooting in 2k.

3. Shooting high frame rates usually means a few things that will kill picture quality, a, windowed sensor, b, high compression, c, more light required.

strategy: try grabbing 100fps at 4 or 5k instead and using a longer lens.
 
Kurt Naeslund said:
Hey thanks Eric,

Thats a good point. I will do more tests, to see if I can find a nice config. If you have any other advice, please let me know!

Thanks,
Kurt
Click to expand...

Kurt, exposure on RED is an equation, that needs to generally be kept in balance:

RESOLUTION (Ks) x EXPOSURE (ISO) x COMPRESSION = QUALITY OF IMAGE

In an ideal scenerio, optimal settings are generally:

6K x 800 ISO x 5:1 = CLEAN IMAGES!

If you lower TWO of those

2X x 800 ISO x 15:1?

You should REALLY overcompensate on exposure:

2X x 320 ISO x 15:1?

The reason is simple:

1) Cropped in at 2K, you are ZOOMED IN on the pixels/noise. So the noise will be BIGGER/CRUNCHIER. So even a small amount of noise, will be proprionally MORE NOTICEALE.

2) Because you are shooting slow-mo, your image WILL BE MORE COMPRESSED. So that SMALL AMOUNT OF NOISE will then be AUGMENTED EVERN FURTHER...by poor compression.

3) So how you do solve this? Try and avoid noise entirely. Shoot with as much light as you can, bathe your sensor with exposure, have everythign to the right, so you are reducing the amount of perceptible noise you can.

4) Lastly, becuase you are aiming for a CLEAN, CLEAN image...triple check your BLACK SHADING...especially or slow mo.

Hope this helps!
 
Yeah, I guess I need to test/work more on this. The footage is aqtually quite ok in Redcine, but after delivery, the noise is quite apparent.

Regards,
Kurt
 
Kurt Naeslund said:
Yeah, I guess I need to test/work more on this. The footage is aqtually quite ok in Redcine, but after delivery, the noise is quite apparent.

Regards,
Kurt
Click to expand...

just double check that you are asking resolve to render out with the full debayer settings. It should look as good coming out of resolve as it does RCX.

fYI: I love the images, they make me feel warm and cosy, remind me a bit of my days in Canada. :)
 
Hey, thanks David :)
Yeah, will check your advice here as well...
 
PS I checked the R3D, and it's perhaps a little under-exposed? At 640 it's quite dark, with histogram far to the left. If you raise image to 2500 ISO, histogram gets exposed more to the right, and image brightens up. Suggests perhaps an extra stop or two could have been added, just to feed sensor more light?

Something to consider, anyway.

Gorgeous shot!
 
Nick Morrison said:
Kurt, exposure on RED is an equation, that needs to generally be kept in balance:

RESOLUTION (Ks) x EXPOSURE (ISO) x COMPRESSION = QUALITY OF IMAGE

In an ideal scenerio, optimal settings are generally:

6K x 800 ISO x 5:1 = CLEAN IMAGES!

If you lower TWO of those

2X x 800 ISO x 15:1?

You should REALLY overcompensate on exposure:

2X x 320 ISO x 15:1?

The reason is simple:

1) Cropped in at 2K, you are ZOOMED IN on the pixels/noise. So the noise will be BIGGER/CRUNCHIER. So even a small amount of noise, will be proprionally MORE NOTICEALE.

2) Because you are shooting slow-mo, your image WILL BE MORE COMPRESSED. So that SMALL AMOUNT OF NOISE will then be AUGMENTED EVERN FURTHER...by poor compression.

3) So how you do solve this? Try and avoid noise entirely. Shoot with as much light as you can, bathe your sensor with exposure, have everythign to the right, so you are reducing the amount of perceptible noise you can.

4) Lastly, becuase you are aiming for a CLEAN, CLEAN image...triple check your BLACK SHADING...especially or slow mo.

Hope this helps!
Click to expand...

Could not agree more with what Nick mentions here.
In fact, this is one of the best summaries I've come across for shooting slo mo with RED
particularly with bringing down the ISO for 2K.

Brian Timmons
BRITIM/MEDIA
 
you can use mini mags to lower the compression further, same with weapon and that can help in the longer tern if you can invest in either or both of those routes
 
Nick's equation is a great way to consider things, but it's not as linear as it appears.

2k is 9x smaller than 6k, so the same noise is 9x bigger in your image.

Noise does not scale at the same rate as exposure, something twice as bright (one stop brighter) might have exponentially less noise. This means open up your lens, you still need to get a good exposure. Lowering the ISO alone does nothing.

Compression seems the most forgiving. 10:1 is nowhere near twice as bad as 5:1. The noise gets blockier with more compression but the rate it changes is hard to quantify. Still, as you lower resolution for access to higher frame rates, there's usually no reason not to lower compression as well. 2k is 9x smaller than 6k in file size as well.
 
Anton Shavlik said:
Nick's equation is a great way to consider things, but it's not as linear as it appears.

2k is 9x smaller than 6k, so the same noise is 9x bigger in your image.

Noise does not scale at the same rate as exposure, something twice as bright (one stop brighter) might have exponentially less noise. This means open up your lens, you still need to get a good exposure. Lowering the ISO alone does nothing.

Compression seems the most forgiving. 10:1 is nowhere near twice as bad as 5:1. The noise gets blockier with more compression but the rate it changes is hard to quantify. Still, as you lower resolution for access to higher frame rates, there's usually no reason not to lower compression as well. 2k is 9x smaller than 6k in file size as well.
Click to expand...

No it's not a linear equation, it's just a guideline.

And clearly, ISO is metadata...but it's also a range/reference of where to expose. A bright 320 is a lot differently exposed than a dim 800.
 
Yep, I know we're on the same page. I think everyone shoots 2k for the first time and thinks they made a mistake, but it's really just a combination of a couple nonlinear changes in the image that you didn't anticipate.

It's also why 3k looks relatively great compared to 2k. It's actually more than twice the resolution. Can't 3k also do 200fps?
 
I really don't try to drop below 4K if at all possible. 200FPS is a lot of FPS and MUCH more than you could ever generally do in film. I still think 32, 48, 60, 72 are sor of "sweetspot" offspeed. Those higher framerates are more for slowing down things you want to slow down with a phantom flex.
But that is just my personal preference.

David

Just looking at the clip.

DEB is your friend and so is contrast. I understand the "lo-fi looks people like these days but with a contrast curve that perceived noise seems to feel more organic.

DEB in RCX or DaVinci would also "reduce" the amount of perceived noise. All that said it does feel exactly right for 2K (think 16mm film but better) and a center cut of the dragon sensor. A stop extra of exposure would have been good, but still very recoverable.

snow.jpg
 
Kurt Naeslund said:
Hello,

Yeah, I am a newbie, but I hope someone can help anyways.
I just recently did a few outdoors shots with our RED Dragon, in 2K and 200fps. Lots of daylight and using Canon L-lenses.

I delivered it through Davinci Resolve.

It seems like the footage has got so much noise? I did try to denoise footage in Resolve as well, but without any luck.

https://vimeo.com/147883385

All help is appreaciated

Regards,
Kurt
Click to expand...

You will get lovely footage if you do the next: Put your iso as low as possible iso 200 and don't under expose, use at least 1/400 shutter time. I did a lot of shooting in 300fps (ws) here is a example:
https://vimeo.com/68138303 commercial and this lovely poledance movie https://vimeo.com/63238582

have fun!

best regards
Robert New showreel (all RED footage) on www.camlight.nl
 
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