BMCC Histogram Vs Zebra?

There are plenty of reasons why I don't always ETTR, especially when I'm shooting in Video mode and there are specular highlights in the scene.

If you expose to the 100% do you not see the proper zebras?

Your are starving your sensor. Is there a reason for that ?

Margus, I'm not sure going to 85% zebra is starving the sensor since it's only a small fraction of a stop lower with the intended goal of ensuring no channel is clipping unintentionally. Have we not seen examples where relying on 100% zebras leads to some results where one of the colour channel clips while the overall scene seemed to be fine?

Those discussions about single channel clipping go back a long way, but I took them at face value without really understanding how one colour can clip given that the sensor is reporting luminance values that are only interpreted as colour according to the debayer process in camera for ProRes/DNxHD or in post for raw.

Rick Lang
Sent using Tapatalk HD

As far as i know if you take some light away you get noise
so in some cases it would be good to have zebras at 100 and dial it bad lets say 1 to 2% by eye
and zebras.

BMC seems like 16 mm film which likes at least 1 stop over exposure.

There are plenty of reasons why I don't always ETTR, especially when I'm shooting in Video mode and there are specular highlights in the scene.

In the early days of discussion about how to get the maximum benefit from the camera, all the indications were that ETTR was the way to go. Since then, the advice has been modified so that ETTR is still best applied to raw or log, but when shooting in video mode, it may be better to expose for the scene closer to a more traditional manner, rather than using ETTR.

Specular highlights can clip the sensor if you wish as they are normally seen by the human eye that way anyway, thinking about strong sun on water or reflecting off chrome on a car, etc. if you don't want those kind of specular highlights to clip, your scene will look quite dark everywhere else. Still you may want that effect if you are shooting waves at the beach.

Rick Lang
Sent using Tapatalk HD

As far as i know if you take some light away you get noise
so in some cases it would be good to have zebras at 100 and dial it bad lets say 1 to 2% by eye
and zebras.

BMC seems like 16 mm film which likes at least 1 stop over exposure.

Yes, I've done that with 16mm film. Open up at least a stop over a traditional exposure when you expose for the middle of the scene or skin tones but that is usually going to be within the limits of the BMD sensor. Now people have the histogram on the camera monitor, it's easier to see the effect of opening up the iris a stop or two more than a scene average exposure. But you still avoid clipping unless intentional.

Rick Lang
Sent using Tapatalk HD

I have a job here that we did in prores with zebra on 95% and it worked out okay i'd say.

You can look it here:



Sure it is maybe a bit on the edge but one can keep that in mind when exposing.

Specially as now we have histogram.

You want to see what your exposure image really looks like, get a waveform monitor, it shows all. BM could add a pop up over image of full screen waveform to show exposure levels across the entire image. Panasonic did that with its AF100, worked great.

You want to see what your exposure image really looks like, get a waveform monitor, it shows all. BM could add a pop up over image of full screen waveform to show exposure levels across the entire image. Panasonic did that with its AF100, worked great.

I would love a waveform, but I fear there is a limit to how much processing power the camera has left in it for these added features?!

Margus, your productions are so good. Enjoyed that Fizz!


Rick Lang
Sent using Tapatalk HD

Remember (at least the list time I uses a BMCC 4K) that the Zebras do not have a 'detect level' in Sony parlance - that is once they appear at the preset exposure level the don't come off - this can be very confusing and make them far less useful.

Remember (at least the list time I uses a BMCC 4K) that the Zebras do not have a 'detect level' in Sony parlance - that is once they appear at the preset exposure level the don't come off - this can be very confusing and make them far less useful.

What? Are you saying that the zebras stay on the screen even when there's no longer clipping?
Perhaps I'm misunderstanding but I've never seen that behaviour on my BMCC.

What? Are you saying that the zebras stay on the screen even when there's no longer clipping?
Perhaps I'm misunderstanding but I've never seen that behaviour on my BMCC.

+1 (If I understood it correctly too)

Remember (at least the list time I uses a BMCC 4K) that the Zebras do not have a 'detect level' in Sony parlance - that is once they appear at the preset exposure level the don't come off - this can be very confusing and make them far less useful.

What? Are you saying that the zebras stay on the screen even when there's no longer clipping?
Perhaps I'm misunderstanding but I've never seen that behaviour on my BMCC.

+1, never seen that.

Yes that was my experience - perhaps it's out of date now - this was on the 4K model in early March of this year. The zebras just stayed on. I can't remember if I was using them for skin or whites now. Also the real-world dynamic range was nowhere near what was claimed. There seems to be a tendency to only protect the highlights - I was trained to set your skin @ 70-75% (67% for mid ethnic tones) then protect the highlights through either compression/limiting (like Sony's DCC) - basically the 'whitest' part of the picture should be 95%. This was often done through light control like nets on windows or just choosing a less 'hot' back ground. Of course sometimes I'll want to let the high lights go but the BMCC seems to do this with far less dignity than other cameras and nowhere near as nice as 35mm. I haven't tried LEE 1s etc with the BMCC though - maybe that would allow it to sing. I see a lot of skin tones creeping up to 85 % these days and I do wonder if that's as a lack of training.

Perhaps you could tell me if there is now an option in the menu to set the range of the Zebras ? If there was I would consider using the BMCC again. I have a job coming up in Jordan and so far the C300 seems to be more suitable. I do have a deposit on an Ursa but would need a couple of test days before I accepted it - still too many unanswered questions for me to take it seriously at this stage. Is the BMCC 4K recording RAW yet ?

Perhaps you could tell me if there is now an option in the menu to set the range of the Zebras ?

You can choose between 75%, 80%, 85%, 90%, 95% and 100% in the BMCC. There's also a histogram now to help with exposure along with some other updates like more white balance options and shutter angles.

Is the BMCC 4K recording RAW yet ?

Yes. The cameras have also been updated with several compressed versions of Prores if you need longer recording times.

What's this BMCC 4K, I keep hearing? You got my hopes up!

It's BMPC 4K (Blackmagic Production Camera)


Jules

Thanks for bringing me up to date guys !

Ah so they now have a 5% range - that must be about a 3/4 of a stop is it ?

Ah so they now have a 5% range - that must be about a 3/4 of a stop is it ?

From 100% to 50% is the equivalent of one stop less, so I believe at the lowest camera zebra setting you can make, 75% is a half stop reduction in exposure. John Brawley mentioned this in another thread if memory serves me correctly. 95% would be only a tenth of a stop less light.

Rick Lang
Sent using Tapatalk HD

You guys are amazing. Just wanted to say that.

Yes that was my experience - perhaps it's out of date now - this was on the 4K model in early March of this year. The zebras just stayed on. I can't remember if I was using them for skin or whites now. Also the real-world dynamic range was nowhere near what was claimed. There seems to be a tendency to only protect the highlights - I was trained to set your skin @ 70-75% (67% for mid ethnic tones) then protect the highlights through either compression/limiting (like Sony's DCC)

It's really important to understand the zebras are based on LINEAR sensor data and ignore ISO settings. None of thoe old rules apply when using linear zebras...they are really more of a tuneable sensor clipping indicator

So 70% isn't like 70% in REC 709 because that isn't a LINEAR space.

Linear based Zebras mean 50% would show at one stop down from clipping....

JB

Hi guys,

today I shot some footage for a corporate with my BMCC. At a certain point (10% battery) I changed the external battery.

So I turned off the camera, I changed the battery and I turned it on again.

And... the low bar disappeared! O_O The one with histogram, meters, ecc.

Now my display is like it was before, just with the tiny bar (ASA, shutter...) on top instead at bottom.

Someone had this kind of stuff?

Do you know how could I fix it?

Hi guys,

today I shot some footage for a corporate with my BMCC. At a certain point (10% battery) I changed the external battery.

So I turned off the camera, I changed the battery and I turned it on again.

And... the low bar disappeared! O_O The one with histogram, meters, ecc.

Now my display is like it was before, just with the tiny bar (ASA, shutter...) on top instead at bottom.

Someone had this kind of stuff?

Do you know how could I fix it?

As stated in the Firmware-Release note: Swipe upwards from the bottom of the screen and the Bar will appear, swipe down to hide it.
On Manual lenses you can also use the Iris Button do so.

Hi guys,

today I shot some footage for a corporate with my BMCC. At a certain point (10% battery) I changed the external battery.

So I turned off the camera, I changed the battery and I turned it on again.

And... the low bar disappeared! O_O The one with histogram, meters, ecc.

Now my display is like it was before, just with the tiny bar (ASA, shutter...) on top instead at bottom.

Someone had this kind of stuff?

Do you know how could I fix it?

As stated in the Firmware-Release note: Swipe upwards from the bottom of the screen and the Bar will appear, swipe down to hide it.
On Manual lenses you can also use the Iris Button do so.

Thanks Lennart!