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KarimNassar

This video illustrates the biggest flaw of the bmcc perfectly

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You didn't read the post above or saw the clip? The BMCCs (and therefore the BMPCCs as well) always record at ISO 800 in raw. They also record at ISO 800 in ProRes, only that then the brightness, DR and noise changes caused by the setting are baked into the compressed file.

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That sets my mind at rest: In raw mode, you can use every ISO you want, without changing the exposure of the clip.

 

Very nice Axel :-)

 

And it makes complete sense doesn't it?

Since iso bumping with digital cameras is an electronic boost of the recorded signal that introduced noise, if that was baked in the recorded footage and not written alongside in the metadata, we would not have a raw file anymore, would we?

Clever trick by Tom.

 

thanks for the research

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btw Axel did Tom provide the increment amount in iso reduction needed to exactly counter the displayed over exposure?

 

Not explicitly. but since ISO 400 and ISO 200 are each a full stop down, you can do the maths:

 

F-number.jpg

Here is the original BM thread.

 

The overexposed images look as if there were more than just two f-stops off a center exposure (it could be though, but with 13 stops latitude ??? ) So maybe it is still the flaw/bug you described in your initial post, that in raw you can't get a decent monitoring. I'd like to test it myself, but unfortunately this is still theory for me in two aspects: My BMPCC didn't arrive yet, and also there still is no raw mode :(

 

EDIT: Perhaps combing the lower ISO with pulling down brightness on an external device will be acceptable.

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Reading a few ETTR discussions it seems to me the jury is still out. i think the consensus is that exposing to the right somewhat is possibly the best scenario.

I've ended up shooting with my pocket camera so the image on the screen looks good, with no zebras (at 95%), then I might open up a half or one full stop on the aperture.

ProRes is less forgiving than raw.

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This is probably the most informative thread I've read in a long time. I've never shot on a Red, or an Alexa, and I'm curious if you expose to the right on those like you have to on a bmcc. From many on set videos I've seen, the monitor is perfectly exposed. Nothing like the bmcc... But then again Red's are $15,000 and up, & Alexa's are... Well, a mortgage. Plus they have on set LUT's more than likely for that.

I use the ETTR technique... Just under the zebras, 800asa, film mode, raw. I'd like to expose a nice balanced shot with my eye, or a histogram on site, but i immediately have to worry about noise. Yes, this camera has loads of DR, but to me I feel like I'm punishing my highlights when i wash it out like they tell you. I pull them down in post, but it looks like the brightest points of the shot are still making a hard left turn. I have all the information, but it's ugly up there. Biggest mistake i ever made with this camera was hooking an Atomos Samurai up to it, and exposing a shot with the histogram.

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I wonder why everyone uses ISO values now? In the old days, every videocam had db values. It was easy. 0db was 0. Negative values were pulled so DR wasn't as good and positive values had gain applied so more noise.

 

Easy.

 

Now people are like "what's my native ISO?" and all the assorted gibberish. Atleast the FS700 let's me switch back to db from iso.

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My BMPCC didn't arrive yet, and also there still is no raw mode  :(

 

I was hoping this was not affecting the bmpcc as it is a completely different camera. But it has the same issue?

 

 I've never shot on a Red, or an Alexa and I'm curious if you expose to the right on those like you have to on a bmcc. 

 

Absolutely not. This is a bug, it is not normal. You will not have this behavior on any other camera.

 

The theory behind ettr, exposing to the right, is the following:

 

- under exposure leads to noise

- over exposure leads to clipped highlights

 

So how can you achieve the least amount of noise but by still preserve your highlights?

 

You expose to the right, meaning you allow as much light as possible just under the point of clipping your highlights.

This allows for your shadows to have the least amount of noise while preserving highlight information.

 

So the monitor feedback you get from this, and the histogram/vectorscope feedback is not over exposed.

Unlike on the bmcc.

 

As I have said before, what they call "ettr" on the bmcc should be called "over expose until you hit zebras because your monitor feedback and vectorscope is wrong"

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Sorry, I'm probably confused. Why?

 

What he did was actually completely correct.

He recorded footage and adjusted the exposure based on the histogram.

Which would have gotten him the cleanest image possible on any camera.

But since the bmcc both visual and histogram feedback is inaccurate and you should use the zebras to adjust your exposure, the recorded footage he got was under exposed.

To bring it back up to correctly exposed he had to up the iso of the footage in post.

And when you boost an electronic signal in post what does it introduce?

see his reply>

 

The noise. That's why I'd assume you're supposed to all but clip the sensor. It's not awful, but don't add any sharpening.

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It's only a decade or so ago that everyone was using film. You didn't see ANYTHING, and had to use external tools like light meters, and judge your exposure based on experience. You didn't really know what you had until the film was processed.

Since DSLR's everyone is used to seeing a beautiful image on an LCD screen.

The simple thing with the BMC is that you can shoot a scene to test, drop it into Resolve on a laptop and in a minute or so see a perfectly graded image. Almost like working with film, but much, much faster.

There is no default noise reduction in the camera by the way. You do it in Resolve. That's better isn't it? You are in control, not the default setting in the camera.

If you see the blackmagic workflow as a bug, that's your right. I like the end result much more than DSLR. It's your loss if you can't be a little more flexible.

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It's only a decade or so ago that everyone was using film. You didn't see ANYTHING, and had to use external tools like light meters, and judge your exposure based on experience. You didn't really know what you had until the film was processed.
Since DSLR's everyone is used to seeing a beautiful image on an LCD screen.
The simple thing with the BMC is that you can shoot a scene to test, drop it into Resolve on a laptop and in a minute or so see a perfectly graded image. Almost like working with film, but much, much faster.
There is no default noise reduction in the camera by the way. You do it in Resolve. That's better isn't it? You are in control, not the default setting in the camera.
If you see the blackmagic workflow as a bug, that's your right. I like the end result much more than DSLR. It's your loss if you can't be a little more flexible.


It's not the workflow that bothers me. The image is rewarding if you nail it, and part of the fun of shooting with this camera
Is the excitement of post and seeing what you can do. I used to be all about the film look.. The film look this, the film look that.
Once I got ahold of a 12 bit raw file in motion it was like lifting the veil. Now, I'm having more fun "painting" these images, than going for that
Typical film look...There's a lot more color range to play with than all of the 8-bit files i worked with for so many years.
So the bmcc has made grading fun again.

The problem with the noise floor on this cam is why you have no choice but to blow it out. Neatvideo is great, yes, post noise
Reduction is far better than in cam reduction, unless you're shooting something with lots of detail. Then all of that post reduction doesn't
Matter because it all goes to watercolor painting smudge.

No one is saying it is a bad camera. For $2000 the image is undeniable & if we could afford it, we'd all probably be shooting on Alexa's.
But I understand where KarimNassar is coming from regarding the actual shoot and representation of what you're looking at vs what you're
Recording. A director isn't going to look at a screen full of white mass and watch his scene unfold on set that way.
Even in the days of film, the director had a properly exposed reference monitor with a set of headphones.

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The problem with the noise floor on this cam is why you have no choice but to blow it out. Neatvideo is great, yes, post noise
Reduction is far better than in cam reduction, unless you're shooting something with lots of detail. Then all of that post reduction doesn't
Matter because it all goes to watercolor painting smudge.
 

There is no difference though. One is automatic noise reduction in camera, the other is user dialled in using software. There is no option but to reduce noise in ALL footage, BMC or DSLR.

Arguably you can get the best out of the pocket camera by exposing to the right. Big deal. It doesn't need to be massively blown out so it's unviewable on a monitor. I'm not blowing highlights and struggling to recover clipped highlights. It's just not point and shoot like a Canon or Nikon DSLR.

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With raw photography, with a conservative exposure, 'ETTC', you also get a misrepresantation and end up in having to change the exposure in post and eventually reduce some noise. Why? 

 

There's a lot more color range to play with than all of the 8-bit files i worked with for so many years.

 

Because what we have here is a 12-bit image. Without any curve applied to the quantization (for the preview!), an 8-bit image can only show less than 5 stops of latitude (256-128-64-32-16, anything below 16 becomes indistinguishable on any common 8-bit display, and in reality none can show values above 240 as well). This is an extremely low dynamic range, and even with a new tone-mapping, the values visible then are a fantasy and by no means represent the true relation between, say, 1354 and 11433 (just above 3 stops in the infathomably depth of 12-bit). 

 

What we are demanding when we call the washed-out images a 'flaw' is effectively a display with an upstream LUT to let us see an incorrect, very much compressed image that we are used to in our tiny 8-bit universe. Something like this is probably built into an Alexa or the like.

 

The workaround to shove the ISOs down also (in the preview) just grabs a very narrow range of what we actually record. The same is true for external devices, if their monitoring is not capable of processing 12-bit raw (which is?), for whatever reason, like Germys Atomos Samurai, which would be suitable for 10-bit, for which the built-in histogram should be reliable, but of course not any LCD viewer.

 

As a digital projectionist from 2000 until 2011, I very often compared the MJEPG2000 DCPs (typically 12-bit) to my own 8-bit ambitious amateur stuff. And no matter if I had used opendcp to convert it or just plugged a laptop to the scaler, the differences were huge. It never was an issue of spacial resolution!

 

Three deliberately provocative theses on where we stand with our appreciation of raw:

 

1. All DSLR bodies have a lot of knobs, buttons and dials as well as complicated menu options and presets. All of these gadgets are phony ways to cripple (potentially) high quality images to some pleasing-looking consumer-jpegs or mpegs. White balance, ISO, looks for different conditions:

Crooks!

There are two things that count, and neither of them live in the camera's body: Focus ring, aperture ring (EDIT: Well, one: 'shutter').

 

2. We still record, grade and view in 8-bit. To shoot raw in order to get a better 8-bit video seems comparable to killing a whale for a cup of cod liver. And we hunt the whale with blindfolds.  

 

3. ETTR will have highlights and some midtones. That the graded images look naturalistic although there are no real shadows could very well be limited to 8-bit. 

 

Germy1979 wrote:

The problem with the noise floor on this cam is why you have no choice but to blow it out. Neatvideo is great, yes, post noise 
Reduction is far better than in cam reduction

 

Unfortunately, afaik, Neat can not neat raw video. Removing noise (useless, redundant data) should be the first step. To do everything right, there is probably no alternative for the BMPCC buyers to buy a full version of Resolve as well. Or ETTR for 8-bit.

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Arguably you can get the best out of the pocket camera by exposing to the right. Big deal. It doesn't need to be massively blown out so it's unviewable on a monitor. I'm not blowing highlights and struggling to recover clipped highlights. It's just not point and shoot like a Canon or Nikon DSLR.

 

This thread is not about the pocket camera.

 

It's about the bmcc 2k.

On the bmcc the gain in quality is significant using this technique, so much that the over exposure till zebra approach is recommended on the bmcc user forum.

And the blown issue is significant as well, and the proposed work around is from the official bmcc user forum as well.

So it is a real issue that needs to be addressed, and it has been, with the workaround, to some extent.

 

Hopefully on the pocket it is not the case.

It seems from your post that it is not, which is great news.

But we would have to wait for the raw recording feature to find out.

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This cam was I'm pretty sure designed for the one man band.. (Despite coming bare bones, lol.). By myself, I don't have a problem shooting a video the way they recommend. On a production where the director wants to watch a reference monitor on the other hand, something like the new Small HD monitors that have LUT's would probably have to happen. Those are almost as much as the camera though, & since the whole concept of the bmcc is basically "affordable" amazing images, that kind of defeats the purpose.

Anyway, Go Denver!

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Hey Karim,

 

Setting the screen to video works and gives you a better idea of exposure and the final image. Just do that and make it look nice on the screen and it will look fine.

 

HOWEVER

 

Just use a light meter. They still work.

 

I never saw the final image through the lens shooting 16 or 35mm. As a director I got to see a terrible standard def video split. But it didn't matter because we knew it was being exposed properly. Exposing to the right is no different from lighting a stop over, just using video terminology. It's not new and for most stocks and pretty much all digital cameras post CineAltas it's been a good rule of thumb. (CineAltas sucked)

 

I took my camera out of the box, put a fresh battery in my meter and shot a music video straight away. Everything was metered and I ignored the back of the camera for everything but framing. It all came out as it was intended. Crazy that 100 year old tech still works huh?

 

Cheers,

 

Toby

 

 

PS REDs are just as bad at giving a false idea of what you are recording and don't get me started about their poor performance in tungsten light. 

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I have an L758Cine by Sekonic for raw shoots. I'm using it with Epics on Saturday. I'd suggest a light meter for all those working with raw video.

 

The reason is that you will know precisely what in your scene is in an out of the DR of your camera, rather than guessing using a screen or histogram. 

 

The 758Cine allows you to set a mid exposure then profile the meter to know how much over and under exposure you have in a given camera, so you'll know precisely what is recoverable and what's not.

 

It's pretty ace, though the ;learning curve is more like a cliff.

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Hahaha You came here Buddy (Karim). Just like I told you... It's a strange behavior... the pocket camera should do the same in raw recording. But for now with prores it's ok. I'm getting the "correct" readings (zebra) from the image in the lcd ;)
 
Best,
JDS

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