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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 :)

Black Shading:A look under the hood

Mark Wilkinson said:
Is there some new info about needing to BS every time we change frame rate or shutter angle?

The current DSMC guide doesn't say so:
  1. Calibration is required:
    • After an extreme change in temperature (+/- 30°F or +/-15°C) from the currently selected calibration map.
    • After an extreme change in exposure time (+/- 1/2 sec) from the currently selected calibration map.




While I admit that theoretically it might make some difference - where did we get the idea that we had to do it for shutter angle or frame rate?

Please advise...
Click to expand...

Is it not widely accepted as good practice?
 
D Fuller said:
Theoretically, there are only two variables that matter: SENSOR TEMP (not the outside temp, that has nothing to do with this) and EXPOSURE TIME (not frame rate).
.
Click to expand...

exact.
In fact I'm talking about because the outside temperature to -10 in the snow, the camera is unable to reach a temperature that would normally have on a set indoors, or at least if it reaches reached after many hours ... so I have to do a BS at low temperatures.

In fact I never change the shutter of 180 degrees .. always pleasant that I want to take in a particular case otherwise.

However, Ivan, try to experiment yourself.
I do not understand why you worry a lot? Have you had problems in post production for the BS?
 
Ivan McCullough said:
Funny, I am not worried. I know from experience what causes the T/E to change from green and thus require a BS.

No problems in post with BS, only problem is waiting 12+ mins on set each time one needs to be performed, (MX), looking forward to having a few in the pocket with Dragon.

If you change frame rate and keep 180 degree shutter you are changing your exposure time btw.
Click to expand...

maybe my English is bad, in fact I'm sure, I apologize ..: (
Obviously, the exposure time change even if you are at 180 degrees and of course also changes color the letter T.
I can tell you honestly that I do not care if it changes color.
I'm going against the trend!?! maybe!
But what I want you to understand is that I personally never had any problems with noise I do with the rest ..
Known only a difference when I put the plug in front of the camera and get up to 12800 ISO ...
 
Ivan McCullough said:
Ok Luigi,

why do you BS at all if you think it does not matter?

Is it the same with the stop-lights and the goal-posts (noise indicators) for you?

Its not a trend you are going against its the recommended operation instructions for the very expensive cameras you own. If you ignore these things you are not getting the best out of the cameras. If you are not interested in getting the best out of the cameras I don't know why you are involved in the conversation.
Click to expand...

Im sure Luigi wants the best. Perhaps lack of time.
 
Hey guys,

great discussion brewing.

I think frame rate needs to be considered.

If you look at he examples in the original post, having a 172.8 degree shutter and going from 24fps to 1 FPS, produces a vastly different black shading. Whereas 172.8 @24 or 360 @24 looks virtually the same.

I rolls a ton of footage on a shoot today at various frame rate, compressions, frame sizes, I rated at 320 all day on outdoor images. I moved the shutter mostly between 172.8 and 72 degrees and the blackshading you see in number one of this post held up really well.

I still ill have to go in and evaluate a bit more critically, but to my eye, everything held really nicely. I'd be much more conservative on a green screen set or capturing night time-lapse, where you really want to give yourself the cleanest images.

It's also harder to see these things when you are hitting the sensor with a nice clean amount of light. I had zero noise and no stoplights all day.

I can't believe how this sensor holds the highlights, it's freakish.

Like you look at it, scratch your head and say, "that's just not supposed to look that good?"


battistella
 
Ivan,
We're talking BS, no histogram or the rest ... or other wonderful tools we have available the camera.
I want you to understand that the image of the real differences I've never seen for speed .. Or better to say that the times I stopped to do the BS I never noticed improvements.
From here I simply ignored the letter T and only in extreme cases do the BS.
So actually I have 4 memories for different shots, 1/48 65c, 1/50 65c, 1fps (time lapse) 65c, and one that I use with motion mount. This is what change.

David,
You can post a real picture of test outside or inside so we can see a difference of BS?
thanks
 
David,
so in case of HDRx, how we should behave?
I've always wondered.
 
luigivaltulini said:
David,
so in case of HDRx, how we should behave?
I've always wondered.
Click to expand...

I guess the blackshading would be for the A track. But I have to say that HDR x is one thing I pretty much never use.

Battistella
 
luigivaltulini said:
Ivan,
David,
You can post a real picture of test outside or inside so we can see a difference of BS?
thanks
Click to expand...

I don't know what interiors and exteriors have to do with it but I'll post something soon.

Battistella
 
I can go from 23.976 up to 74.93 and E stays green. It does turn yellow+ when I go above 74.93. In that case, I would probably use another calmap. I do like the idea of the Dragon selecting a different calmap when it needs to, assuming you have it already created. Or maybe prompt you asking if you would like to use the proper calmap. Again, would only prompt if you had created one.
 
My personal experience with blackshading is to do it when I install new firmware.

That said, I seldom ask my cameras to jump through hoops. By that I mean, I may shoot different timebase (23.976, 180 degree shutter or 47.952, 360 degree shutter) and on occasion shoot varispeed high frame rates.

I occasionally saw some yellow Ts with older firmware on the Epic X, but with Dragon I've seen nothing but green, even shooting at the best compression ratio allowed (in case that has anything to do with anything.)

I respect anyone trying to max their recorded image, but for me, shooting more simply is less time consuming and I'm happy with my images.
 
Stacey Spears said:
I do like the idea of the Dragon selecting a different calmap when it needs to, assuming you have it already created. Or maybe prompt you asking if you would like to use the proper calmap. Again, would only prompt if you had created one.
Click to expand...

That would be GREAT!
 
Since the core temperature is fairly regulated I don't see much of a need to do it unless you are experiencing massive temperature shifts like +/- 50 degrees. Like going from say a nice 75/80 degree Southern California day to maybe shooting at 35/40 degrees or lower in the snow.


First two lines on any Dragon firmware udpate:

[/quote]IMPORTANT:

You must black shade an EPIC DRAGON or SCARLET DRAGON after upgrading it.[/quote]


Black Shading isn't really a big deal anymore because it's been shortened drastically in the time it takes to run it.

Basically before shooting anything I setup the 4 shutter speeds/angles I will likely use the most and fire off the Black Shade.

For me that's usually:

-1/24th (for that moment when you need 1 more stop to get what you need)
-1/48th (standard 180 degree shutter for 24fps projects)
-1/144th (standard 180 degree shutter for 72 fps, which I like)
-1/200th (standard 180 degree shutter for 100fps)

The interesting thing here is that a few of those are within a single Black Shades operating ranges, so it's just me being "cray cray".

I might swap out one of those for maybe a 1/1000th or faster angle. Also, I might toss out one or two of those to store Motion Mount shutter speeds/angles I like. Just depends.
 
I like to setup a 1-second exposure ,in addition to my 1/48th, just in case I get the urge to shoot some timelapse. I have not settled on the other two yet.

Given the volume of posts on black shading, in general, I suspect people are using black shading to try and solve other issues they are seeing.
 
David Battistella said:
Hey guys,

great discussion brewing.

I think frame rate needs to be considered.

If you look at he examples in the original post, having a 172.8 degree shutter and going from 24fps to 1 FPS, produces a vastly different black shading. Whereas 172.8 @24 or 360 @24 looks virtually the same.
Click to expand...

I'm not sure that's what your test shows. It shows vastly different noise profiles on the recorded material, but how do you know that is due to the cal map? Isn't it just as likely that something about sitting idle for 1/2 second between frames has an impact on noise?

I'm not saying I know this is the cause, just that there are more variables than you seem to be looking at.
 
D Fuller said:
I'm not sure that's what your test shows. It shows vastly different noise profiles on the recorded material, but how do you know that is due to the cal map? Isn't it just as likely that something about sitting idle for 1/2 second between frames has an impact on noise?

I'm not saying I know this is the cause, just that there are more variables than you seem to be looking at.
Click to expand...

i guess all all it really shows is that at that particular frame rate, the maps produces pretty much a flat black field. I've shot tests on MX with the absolute wrong cal map (like if I were to shoot at 24, 172.8 degree shutter with Calmap #3)

one could call it and unusable image or a very interesting look. So people could end up cooking looks with calmaps as well because it's not just about noise but color variation as well. (At least it was that way with MX, and I've seen at least one on dragon) in the same way people could bleach bypass film to create stylistic pieces.

So I look at this as a creative tool as well.

Battistella
 
I think RED has been pretty clear in the past with MX and now with Dragon. It hasn't been a real mystery.

You have to Blackshade after a FW upgrade.

-Large swings in shutter angle or sensor temperature.


I do them as:

1. Part of prep anticipating frame rates and temperature.
2. Between 'regular" operation and time-lapse (especially night time-lapse)
3. At temp/shutter for green screen
4. Change of altitude.

After my shoot yesterday I don't think anything in full Daylight going to faster shutters (from 172 down to 72degrees) was just fine. No issues at all.
 
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