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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 :)

Epic noisy at 2K

That's an interesting theory John. I'm wondering why you think the RCX at 320ISO would be a more accurate representation of what the sensor sees. is the epic 320ISO at 300fps?
 
The sensor is native 320 ISO - obviously there's best highlight versus shadow protection and mid-gray balance at ISO 800 which is how many prefer to shoot, but there is a degree of compromise about that.

The sensor has a noise floor which creates a pattern of random data even with the lens cap on. Shoot a second with the cap on and take it through RCX-Pro, you'll see what I mean... its not black, its the inherent noise of the sensor system that you see. Its your job to decide how to deal with that in your grade...

If I expose an image very very low the significant data will occupy just a small part of the histogram to the left. Expanding it out through increased ISO, FLUT etc expands that noise floor too. Again, try it on your black clip - rendered at a high ISO, even with a good black shading done there will be a nice bell curve distribution of noise, and your image data is being affected by that. The noise is inherently random too and changes from frame to frame, which makes it a tall order for the wavelet compression to go to work on.

Back to our real world example, exposing at ISO800 allows less light onto the sensor than exposing at ISO320. At 320 more signal is applied to the system, but the noise floor is constant. Better signal to noise means a cleaner picture. A cleaner picture is a more achievable task for Redcode to get its teeth into. So rating the camera lower when your visible pixels are so much bigger at 2k gives you a two-fold win: Better signal to noise ratio to eliminate the pixel-by-pixel noise/grain of the sensor, and better compression as the wavelet algorithm wastes less effort dealing with complex but irrelevant data.
 
I rated at 640btw and redlog film is taken to 320. It's not only the noise in the black which I can crush away but in the mids. I will try 400ASA next time, it will help a little I'm sure. What I don't understand is why the monitor image is clean and the recorded image not. It must be compression?
 
Just tried 2K shooting with my canon 70-200, which is really sharp. The image sharpness is quite ok, could be a bit sharper and nicer, but not really bad. But the noise, even at 320 is just way to much. This thread is quite old, but there is still enough to win here. The noise is war more bad than 5K (which is logical), but i hope red is still working to improve this. And hope the bring out a s16mm frame size (like 2.5K), which would probably help a bit as you oversample more for HD output
 
Is anyone else still experiencing this? Just updated my camera to 3.0.7 and still the noise is very relevant.

Thoughts anyone, black shaded at 240 FPS rc 6:1
 
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