How to do a Black Shading Calibration?

[David Cho]

I understand that when upgrading to build 20, I need to do a black shading calibration. Is there any way to do this with using the red accessories (the evf and the lcd)? Could someone tell me the best way to do this?

Thanks.

[Jeff Kilgroe]

In the System Menu > MAINTENANCE > BLK SHADING you'll find black shading calibration. You will need a blank, camera-formatted CF card inserted, or I suppose a RED drive would work too. You will want the lens cap or camera body cap on for sure and possibly take other measures to guaranty that no light will hit the sensor. Other than that, it's an automated process, the camera does it all itself.

You need to do a black shading calibration anytime you load new firmware, even if you roll back to a previous version. I don't know if it makes much difference, but I always do the black shading after the camera and sensor have warmed up a bit.

[Jarred Land]

Jeff is correct... do a black shading when your temperature changes environments from when it was last black shaded... it helps, you might not be able to always see the difference, but it's there.

body caps is always good or lens completely stopped down just to make sure... and I usually throw a towel or shirt or something over the front of the camera just for extra measure as the calibration process is extremely sensitive to light.

[Martin Weiss]

While we are at it, when doing the black shading calibration, it throws up a warning that one should only do this step when prompted to do so.

Can anything be damaged by excessive calibrating?

I occasionally have to do a new calibration when doing longer exposures. And then another one when I go back to more normal exposure times.

Coming to think of it, it would be great if one could store a number of black shading settings for different exposure rates. Or - even better - make the camera automatically apply the corresponding black shading, depending on the exposure time.

[Jarred Land]

Black Shade all you want its good to do.. it wont hurt you :)

Black Shading storage/import/export is something thats been on the list since forever.. maybe some day. It's kinda like auto white balancing though... even though you might be using the same lights any two days or setups will never be exactly the same. Too many variables :(

[Andrae Palmer]

Jeff is correct... do a black shading when your temperature changes environments from when it was last black shaded... it helps, you might not be able to always see the difference, but it's there.

body caps is always good or lens completely stopped down just to make sure... and I usually throw a towel or shirt or something over the front of the camera just for extra measure as the calibration process is extremely sensitive to light.

If you do black calibration in a cold environment and film in a hot environment... will this cause the vertical line problem? See attached images below:

http://farm3.static.flickr.com/2640/3832505482_bab505118a.jpg (http://farm3.static.flickr.com/2640/3832505482_bab505118a_b.jpg)

http://farm3.static.flickr.com/2573/3831389737_f5645c76b4.jpg (http://farm3.static.flickr.com/2573/3831389737_f5645c76b4_b.jpg)

I would like any information on how to mitigate this from happening. This is the first time I've heard about changing black calibration per temperature environment so its extremely helpful.

[Jeff Kilgroe]

Sensor performance changes with sensor temperature. I've always thought it best to calibrate the sensor when it's running at or very close to the temperature and conditions to where I'll be shooting.

Andrae, I've seen vertical line patterns within the sensor noise on under-exposure in the past. Especially before build 16. But that vertical line you have there looks like something else entirely. Have you talked to RED support about that?

[A. Clint Litton]

Those lines look a bit wild...the lines I've seen from underexposure didn't seem as sharp and well-defined, but were spread out a couple of places. Could you see those lines during shooting or on playback? Or only after processing? Sounds like a job for the workflow wizard...

Btw, those are beautiful shots, Andrae. Were those shot with RPPs or something else?

[Andrae Palmer]

Have you talked to RED support about that?

Yes stil waiting on feedback from Sean Ruggeri to advise me on how to mitigate the problem from happening again.


Those lines look a bit wild...the lines I've seen from underexposure didn't seem as sharp and well-defined, but were spread out a couple of places. Could you see those lines during shooting or on playback? Or only after processing? Sounds like a job for the workflow wizard...

No I couldn't see the lines while recording... even at 1:1. Only popped up in post with REDCine and REDAlert.. the lines could be missed at 1/2 res high.


Btw, those are beautiful shots, Andrae. Were those shot with RPPs or something else?

Thanks! Yes those clips were shot with the 100mm RPP. I was kind of pissed at this problem due to ruining those clips... now I'll have to get into shake and rescue these. I've had this problem before on RED # 1888 last year... these clips were from REd # 6353. So this seems like a general problem to me. Usually disappears with a black calibration... but how do I know what situations will likely cause it to happen again?

[PatC]

Andrae what build were you on when this line happened?

[David Cho]

Thanks a lot Jeff! Thanks guys

[Vincent Visser]

A few days after up-grading (and black shading) to build 20.1.3 one off our camera’s also showed the vertical line issue Andrae Palmer described during a camera prep. I saw the big line in the middle during playback. It wasn’t the cf-module or the red-drive, since the line was recorded on both media. After one reboot the problem was gone. We also did an extra black shading for the security, and wrote Red about this vertical line issue. They also advised us to do a black shading and described the problem as an odd case. I haven’t seen the vertical lines in the footage after this incident.

Vincent Visser

[Robert Guthrie]

I get the line sometimes when shooting here in the Summer time (AZ), especially outdoors. I always assumed it was a heat issue.

[Alexandre Bouchard]

Also got this problem in the middle of a shoot.

build 20.1.3

Link to the clip ->
http://www.zapimage.com/web/RED_Vertical_Line_Problem.mp4

[Matthew Riggieri]

I belive I was told by Sean Ruggieri that you should always restore the factory black shading before doing a new calibration.

[David Battistella]

Also got this problem in the middle of a shoot.

build 20.1.3

Link to the clip ->
http://www.zapimage.com/web/RED_Vertical_Line_Problem.mp4


But we were told that film scratches would be a thing of the past with crystal clear digital technology! :)

wow. Maybe it's films secret way of fighting back.

How did you repair it?

David

[Yousuf Abbasi]

Is it necessary to do Black Shading Calibration when getting a new camera from RED?