Image noise increases at different shooting formats

[Dominik Muench]

Hey Guys,

after having issues with extreme noisy images during slowmotion work, as discussed in this thread:

http://www.reduser.net/forum/showthread.php?85957-Slowmo-footage-very-noisy-all-of-a-sudden&p=1069838#post1069838

I did a couple of tests over the weekend and found that the level of noise doesn't seem to be so much an issue of the frame rate but actually the shooting format.

my Epic is cleaner at 96 FPS, 5K and 12:1 compression than it is at 2K 240fps, 12:1 even with custom black shading.
I tried different slowmotion tests at 5K, 5K-WS, 2K, 2K-WS and at 2K the image shows the most noise as you can see in this short sample:

http://www.blacksun-productions.com/leah.mov

Is this a common thing amongst the Epics considering the camera crops into the sensor to achieve the different shooting formats ?

 

[Frank Cueto]

This might be due to the benefits of supersampling. as you lower you resolution you loose those benefits. Perfectly normal me thinks.

 

[Dominik Muench]

Hi Frank,

I assumed this might be the case, but to such a severity ? did you check out the sample clip ? I dont really have any other 2K footage from people to compare it to but the results I got seem to be VERY noisy. Just worried there might be an issue with my camera.

 

[Mestizo Devon]

Hey Guys,

after having issues with extreme noisy images during slowmotion work, as discussed in this thread:

http://www.reduser.net/forum/showth...y-noisy-all-of-a-sudden&p=1069838#post1069838

I did a couple of tests over the weekend and found that the level of noise doesn't seem to be so much an issue of the frame rate but actually the shooting format.

my Epic is cleaner at 96 FPS, 5K and 12:1 compression than it is at 2K 240fps, 12:1 even with custom black shading.
I tried different slowmotion tests at 5K, 5K-WS, 2K, 2K-WS and at 2K the image shows the most noise as you can see in this short sample:

http://www.blacksun-productions.com/leah.mov

Is this a common thing amongst the Epics considering the camera crops into the sensor to achieve the different shooting formats ?

Do you mean noisy as in SEXY:yikes: or....
I didn't notice any noise:laugh:

 

[Dominik Muench]

Mestizio.....haha sorry I know the sample footage isn't exactly a professional clip or a decent test by any means, It was from a run and gun shoot last week but If you look at the dark hair and the rocks in the background...there is considerable noise :/

 

[Frank Cueto]

Yep, Leah looks just how I would expect her too at that Res. Remember you are cropping on the sensor as well using less of your glass (mind you the loss of light and high compression ratio). I can notice noise just by switching from 5k to 4K on almost any footage, so yes, it is somewhat noticeable. This is exactly why we always process everything at 4K and then down convert to HD, usually picking different scaling filters depending on the content/delivery.

Now, that bit of noise is easily handled by any NR tool worth its price.

try it.

 

[Mike P.]

The noise should be more than twice (~2.5x) as noticeable since your pixels (including the noise) is literally magnified by a 2.5x difference going between 5k and 2k.

Try this -- put your 2k footage on a 5k timeline (so that it looks like a centre crop) and render out to 1080p... I bet the "difference" in noise will not be noticeable. 12:1 only make it SUPER noticeable at 2k (less noticeable at 5k because there are so many more pixels to use in the compression stage.)

EDIT: By the way, if that's your day job (filming women in bikinis in slow-motion), that's a pretty awesome way to make a living.... Just sayin'.

 

[Dominik Muench]

thanks guys, thats what I thought when it came to the sensor cropping. I ll give this a try. In the past for these videos I went straight from raw to ProrResLT 1920x1080 and edited in final cut.

Can you recommend a good noise reduction tool Frank ?

haha Mike not sure if you can call this "making a living" but it gets me by its more projects on the side for magazines and websites.