Welcome to our community

Be a part of something great, join today!

Register Log in
  • 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 :)

Black Shading Noise Real-time Indication

Zeb B

Zeb B

Well-known member
Joined
Sep 30, 2011
Messages
4,933
Reaction score
1
Points
0
Location
In The Moment
Recently I shot a bunch of footage that when looking at it in CineX the histogram shows a perfect 'hump in the middle" exposure curve while the left noise level indicator (goal post) was pegged and the footage extremely noisy. I know that I would have not shot with the shadow level vertical bar screaming red so this points to a Black Shading or some non-exposure level related issue.

Questions:

1. is there any indication that there is a Black Shading noise issue during the acquisition of footage or is this like lamp ballast flicker - it is only seen during playback on a computer?

2. If there is currently no indication that Black Shading induced noise is ruining your entire day's shoot, would that not be something to add to the monitor screen? Seems important.

3. RED TEAM: When is black shading required? Switching from 48 to 75fps? 75 to 96fps? My work calls for constant frame rate switching - please don't tell me I have to perform this 10 minute function between each switch. Is there an official RED, specific and comprehensive White Paper type statement on Black Shading somewhere? The Epic manual only provides the basic "how", not the "why" and "when".

4. Does a high shutter speed add to the non-monitor displayed noise level? If so, at what point - what are the rules for shutter speed / noise?

5. Fundamental question: Is ALL recorded noise displayed in the monitor bar levels during acquisition? If not, what types are and which are not?

Thank you for the assistance
 
Josh Beadle said:
4. Does a high shutter speed add to the non-monitor displayed noise level? If so, at what point - what are the rules for shutter speed / noise?
Click to expand...

Josh, I remember one shot that had a lot of noise even though the histogram was a perfect mountain in the middle was shot at a 9 degree shutter. I did the calculations and that comes to 1/960 shutter speed. The shot was in sunlight but 1/960th seems too high to give the mountain in the middle histogram I saw. ISO was set to 800 so that isn't the issue. Does the meta data show was f-stop you were at? (don't know if that is supported yet actually).
 
It seems to me that the red (color) noise level meters in the 5" Touch Screen monitor display only what is present BEFORE pushing the Record button. If Black Shading and Shutter induced noise is generated during the Record process then it follows that it would not be represented in the Monitor. Would love to have RED TEAM state what is/isn't monitored for noise and reply to the numbered questions in the OP.
 
Yeah I know there has been lots of discussion on these issues on the forum, but I have yet to see a Red team member respond to these type of questions. +1
 
FPS doesn't affect black shading but shutter time does.
More so under 1/20th or so than at higher shutter speeds.
 
Deanan said:
FPS doesn't affect black shading but shutter time does.
More so under 1/20th or so than at higher shutter speeds.
Click to expand...

Thanks Deanan. So that leads me to two questions:

1- If I'm going to be shooting multiple overcranked speeds, what is your best black shade recommendation? Is 1/48th good for all day? Or is it better to shade at a higher shutter speed?

2- If I'm shooting at low speeds - 1/12, 1/6, 1/18 does each of them need a separate black shade? If that's not possible, what would the best policy be for that scenario?

And that brings up a third question:
3- If multiple shadings are required for the best picture, could there be a way of saving and recalling those settings?
 
if we do a lot of shooting primarily at 96th and higher shutter speeds (and always at 23.976), is it recommended to black shade calibrate at 96th instead of 48th? or does it really only matter at the super low shutter speeds 20th and below like deanan posted earlier.
 
if i remember well there was a thread that claimed that you should black shade for the longest exposure times of the day... hence i assume that one would be good for the faster speeds.....


couldnt find the before mentioned thread anywhere though...
 
D Fuller said:
Thanks Deanan. So that leads me to two questions:

1- If I'm going to be shooting multiple overcranked speeds, what is your best black shade recommendation? Is 1/48th good for all day? Or is it better to shade at a higher shutter speed?

2- If I'm shooting at low speeds - 1/12, 1/6, 1/18 does each of them need a separate black shade? If that's not possible, what would the best policy be for that scenario?

And that brings up a third question:
3- If multiple shadings are required for the best picture, could there be a way of saving and recalling those settings?
Click to expand...

1. Use 1/48. I'd maybe consider another black shade if you were going to much higher shutter speeds like 1/1000th or so.
2. Go for the longest shutter time if you're switching between them. But redo it for 1/48 when you go back.
3. That is coming.
 
Hello Deanan,

Any chance of getting the OP questions answered in long form? These are technical issues that really need an official RED Engineer answer to. I would like to have a Best Practices document to follow rather than trying and failing again.

Thank you for your time,

-Josh
 
Can I make a pre-emptive request to have the camera handle most things blackshade-related in an automatic way? (with an option to override of course...) i.e. to automatically load an appropriate blackshade for the current shutter speed, and something like a "Blackshade All" option that runs through a series of relevant shutter speeds and stores them in memory. Might also be good to have recommendations on what sensor temperatures to run something like this at...

Saving/recalling of blackshades, adjustments for shutter angle/integration time etc. is a potential source of information overload and error that's really more of a background operation than about putting money in front of the lens. As long as we have the ability to do it ourselves when needed, I'd rather have the camera handle this stuff.
 
Josh Beadle said:
Hello Deanan,

Any chance of getting the OP questions answered in long form? These are technical issues that really need an official RED Engineer answer to. I would like to have a Best Practices document to follow rather than trying and failing again.

Thank you for your time,

-Josh
Click to expand...


Sure, but first you have to distill them down to core questions and not all intertwined like they are now.
 
Deanan said:
Sure, but first you have to distill them down to core questions and not all intertwined like they are now.
Click to expand...

I am looking for the sum technical knowledge that RED has on Black Shading as it relates to Epic. My OP can just be an opening set of questions on the topic. Any results of internal tests that would assist Epic users with understanding Best Practices and known issues. If would be very helpful if this critical technical information can be presented in an official sticky White Paper style document (that can be updated) instead of brief informal comments buried in different forums. It seems this would be a great way to reduce repetitive questions and the wasting of valuable RED engineering time.

Thank you for you time and consideration
 
Deanan said:
1. Use 1/48. I'd maybe consider another black shade if you were going to much higher shutter speeds like 1/1000th or so.
2. Go for the longest shutter time if you're switching between them. But redo it for 1/48 when you go back.
3. That is coming.
Click to expand...

Thank you, that's very helpful. I'm very pleased to know that the ability to save & recall BB data is coming.
 
Good Afternoon Deanan,

I'm in New Zealand for 3 weeks of shooting. I really need to know what is the total RED technical / testing knowledge on Black Shading as I have outlined above. I'm not sure your reply: http://www.reduser.net/forum/showthr...l=1#post867800 is a response to this request since it does not cover my questions and is not comprehensive in topic coverage.

If RED has not conducted any organized testing on Epic / Black Shading involving changing frame rates / RC / / Resolution / Shutter then please let me know so I know how to spend my time tomorrow (location shooting vs testing in the hotel room). If there has been structured testing at RED then please forward that information so I can make a productive day of tomorrow and return with quality, noise free footage.

Please let me know either way.

Respectfully,

-Josh
 
You must log in or register to reply here.
Back
Top