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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 :)

Dragon Black Cal - strange noise pattern at 12800

Has RED Engineering ever posted or printed The Final Word on Black Shading? Seems strange that we are still having debates about this. It's Science - not Faith . . . so there should be a binary process rather than personal interpretation and opinion. Much like "how do I correctly power up the Epic?"
 
Zeb B said:
Has RED Engineering ever posted or printed The Final Word on Black Shading? Seems strange that we are still having debates about this. It's Science - not Faith . . . so there should be a binary process rather than personal interpretation and opinion. Much like "how do I correctly power up the Epic?"
Click to expand...

I agree, it should. Which is why I think it should be part of the firmware upgrade process, If you have to do it once the firmware is upgraded then why not have it set as part of the upgrade process as a foolproof method?

The camera just needs to wait until its at the optimum temp (again this should not be subject to personal interpretation and opinion) then it asks what 4 shutter settings you want (1 for MX), et voila, no confusion.
 
Zeb B said:
Has RED Engineering ever posted or printed The Final Word on Black Shading? Seems strange that we are still having debates about this. It's Science - not Faith . . . so there should be a binary process rather than personal interpretation and opinion. Much like "how do I correctly power up the Epic?"
Click to expand...


- do it often : on every upgrade, on every prep, on every shutter speed change, on every cal temp change (freezing temp 45/ warm temp 65/ hottest temp 70), on a weekly basis.
- stay grenn/green

Pat
 
Zeb B said:
Has RED Engineering ever posted or printed The Final Word on Black Shading? Seems strange that we are still having debates about this. It's Science - not Faith . . . so there should be a binary process rather than personal interpretation and opinion. Much like "how do I correctly power up the Epic?"
Click to expand...

Part of the issue IMO is that firmware keeps improving and changing to make things better and easier. So the "best practices" need to evolve as well.

But YES - I think there needs to be a better FAQ on RED's website. Focused on real world, best shooting practices, etc.

We can throw all the stones we want at ARRI ALEXA - but they did a very good job with their FAQ to help users - http://www.arri.com/camera/alexa/learn/alexa_faq/

A RED version of that FAQ would help a lot of folks out there.
 
Maybe it cause I don't get my hands dirty and have only ever done it muself once but I just dont know this.

If a black shade is done, is there any way the camera knows if its good or not, ie that there was no light/radiation leak while the BS was done?

If the answer is no then is it possible to shoot while the temp signals are green/green and the cal map is not good?
 
Ivan McCullough said:
Maybe it cause I don't get my hands dirty and have only ever done it muself once but I just dont know this.

If a black shade is done, is there any way the camera knows if its good or not, ie that there was no light/radiation leak while the BS was done?

If the answer is no then is it possible to shoot while the temp signals are green/green and the cal map is not good?
Click to expand...

The camera assumes that you have zero light hitting the sensor when creating the CalMap.

So ... yeah ... if you don't black shade correctly - you will have issues. That said - it's pretty hard to screw up.
 
The black shading is designed to fail on first pass, if light is entering the camera. Best practice, is no lens, but cap on mount, with a black cloth around mount, for Justin Case.

Thank you very much

fury
 
Mark L. Pederson said:
First of all .... you are looking at a SCALED image from the sensor on a low resolution display. So, sure ... SOMETIMES it will show you - sometimes you won't see it. Further, on some firmware builds I have seen some funky-ness on "extreme" high ISOs.

I disagree. By the very nature of how the CAL: T/E meter works - it's is, based on all my tests, the BEST way to know if your map is wrong - more accurate than cranking the ISO.

The CalMap cares about only two things - sensor temp and exposure time. The camera can 100% check those values against the values used to create the currently loaded CalMap - and that is all that matters.

So ... I fail to see WHY you would even bother to crank up the ISO for visual check - unless your CAL: T/E was showing you a YELLOW indicator - that is the ONLY time I ever do it. Because if you are GREEN/GREEN you are good to go.
Click to expand...

As you've said, all that CAL T/E says is that camera temperature and exposure (shutter) are within the acceptable Black Shade window compared to when calibrated. It doesn't show how absolutely even the shade is or if there are dead/stuck pixels since the last calibration (which can happen any time, not just when a high energy radiation zaps it at high altitude). You can punch in 1:1 on the display too so it isn't scaled.

Anyway it's not either/or. I use BOTH the ISO crank up AND CAL T/E green/green. They tell us different things. Even you've used it when CAL T/E goes yellow?

In some run & gun shoots I've done, it was a very useful quick check when there wasn't time to Black Shade before rolling.

I don't worry about the slight flicker at 12800 as it has never translated into problems on footage.
 
Mark L. Pederson said:
But YES - I think there needs to be a better FAQ on RED's website. Focused on real world, best shooting practices, etc.
Click to expand...

Working on something and I've been in communication with Red about it too. Should have it done next week now that I literally just finished a job up.
 
Thanks for all the responses guys. What worrys me is that I think it is valid to check the noise pattern at high ISO such as 12800 as it can reveal issues that are not as obvious at low ISO.

Of course nearly all issues dissapear if you are shooting between 250 and 1000... however the other day I was doing some low light testing and I noticed some strange vertical lines at 4000 ISO. I put the cap on, shut the aperture, and jacked up the ISO to 12800. Lo and behold those lines were there. even once the camera warmed up these strange lines remained. Several black calibrations since then and it seems better, but I dont think I could justifiably use this camera beyond 3200 ISO in any situation whatsoever. These fixed noise patterns are far too obvious...

What is also worrisome is that even when the black cal indicators are green, these vertical lines are visable (even at lower ISO) after the camera booted up. A visual check of ISO is therefore very necessary, and by relying on automated tools perhaps in this case unwise.

That being said, wtf are those vertical lines...??
 
Photo of the lines Ivan? Do they appear on recorded material?
 
yeah i would record a shot where you see them and then look at the image in full res in RCX to see if its really there or if its part of the downscaling in monitor.....
 
It's definitely in the footage when recorded. I have managed to get rid of the lines more or less, however now the image flickers when I use it between 3200 and 5000 ISO... Like the lump change of film in the theater (if that makes sense).

I don't see any issues between 250-2000.
 
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