Black Shading

[Cid J Salcido Uyarra]

What r the main reasons to Calibrate Black Shading under "Current Exposure Settings" v "Default Black Shading"?

 

[Roy Gregorio]

Does it matter what ISO is set to when performing black shading? The manual says "After calibration with a lens cap on and ISO set to maximum, the sensor should show a uniform noise profile over the whole area without any falloffs on any side."

But it also says on the previous page, "To calibrate the sensor the image should be as dark as possible." So those two sentences kind of conflict each other. Should it be set to maximum ISO?

 

[Shapour Daneshmand]

I'm also confused on this.
Could some one from RED explain "black shading", reasons, instances and procedures please?
thanks

 

[daniel caruso]

The way I have known this, is that default is calibrated at a certain temperature, at 24FPS 1/48th shutter. So with this setting, regardless of your current exposure settings, this setting with calibrate on those exposure values.

Current exposure settings is what it says, your current exposure values, which, I believe is FPS and SHUTTER. Though I have read that ISO is best to set high, and sometimes read it doesn't matter.

Regardless I have gotten great results in low light for noise using the current exposure settings, highest ISO setting, PL cap and user calmap. If you search there have been a bunch of threads with black shade comments.

 

[Mike Lary]

Does it matter what ISO is set to when performing black shading? The manual says "After calibration with a lens cap on and ISO set to maximum, the sensor should show a uniform noise profile over the whole area without any falloffs on any side."

But it also says on the previous page, "To calibrate the sensor the image should be as dark as possible." So those two sentences kind of conflict each other. Should it be set to maximum ISO?

It's been said that format is irrelevant and it's also been said that you should always calibrate at 5K, so you can pick your answer there. I always calibrate at the highest resolution.

The ISO reference (cranking it up to maximum) is for testing the effectiveness of the calibration. It has nothing to do with the calibration itself. By cranking up the ISO with the lens cap on, you're just making it easier to see if there's any non-uniformity.

The original advice from Red (Deanan specifically) regarding when to calibrate was:
1) upgrading to new firmware
2) big ambient temperature changes
3) long exposure times (longer than ~1/15th sec)
4) very short exposure times (shorter than around ~1/1000th)
5) beginning of a project
6) as often as you feel like

It's unclear what constitutes a "big" temperature change. I've only been able to test +/- 15 degrees and seen no difference.