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Blackmagic Micro Cinema Camera Raw vs Canon DSLR CR2 raw stills

cr2 raw dynamic range

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#1 Evan Richards

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Posted 17 October 2017 - 07:29 AM

I've shot a lot of stills and have some experience with Canon raw files. How do these compare with black magic raw video? The stills are higher resolution obviously but is the dynamic range comparable? Does Blackmagic raw have better dynamic range?

 

Please advise.

Thanks!


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#2 Tyler Purcell

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Posted 17 October 2017 - 01:37 PM

Canon doesn't do camera raw in "video" mode only in still mode.

Blackmagic has Cinema DNG Raw which is a folder full of Tiff files.

Cinema DNG isn't the same style of RAW at all. Cinema DNG is a compressed RAW, which makes it a lot better for video.
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#3 Evan Richards

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Posted 17 October 2017 - 01:52 PM

Canon doesn't do camera raw in "video" mode only in still mode.

Which is why I specifically asked about raw stills in the title and body of my post.
 

Blackmagic has Cinema DNG Raw which is a folder full of Tiff files.

Actually it would be a folder full of DNG files.
 

They're not very similar actually... Cinema DNG isn't the same style of RAW at all.

They are similar because they are both raw image file formats that can both be opened and manipulated with adobe camera raw. I was asking about the comparison in dynamic range which should be an easy correlation to make.


Edited by Evan Richards, 17 October 2017 - 02:05 PM.

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#4 Vladimir Cazacu

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Posted 17 October 2017 - 05:23 PM

bmcc-bmpcc-ei.png

This chart should give you a rough idea of what the BMPCC/BMCC/BMMCC are capable of in terms of DR (they all use the same sensor). ASA 800 is the native ISO, the line in the above image represents middle grey.


Edited by Vladimir Cazacu, 17 October 2017 - 05:24 PM.

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#5 Evan Richards

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Posted 17 October 2017 - 05:38 PM

Right. I knew it was advertised at 13 stops. It's interesting because if I'm reading this right, this chart would seem to indicate it would be best practice to shoot at 1600 ASA in brighter light because you'd get more latitude in your brighter areas.

 

Still doesn't answer how this compares to Canon RAW CR2 files though. Hmmm.

 

Thanks!


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#6 Vladimir Cazacu

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Posted 17 October 2017 - 05:51 PM

Your thinking is correct but ASA1600 on Blackmagic Cameras is basically ASA800 + 1EV of digital gain, so it isn't really all that usable due to FPN and dramatically increased chroma noise and all sorts of nastiness.

ASA800 offers the best bang for buck in terms of highlight protection.

 

Above ASA800, the Canon cameras apply analog gain, so the performance should be considerably better than what BMD is offering at high ISO settings.

 

Now, not to be rude or anything but your question doesn't really make sense, seeing as how the dynamic range of "Canon RAW CR2 files" differs from camera model to camera model (if you are asking about the actual file format itself and how it differs to CinemaDNG...that's well above my pay grade ^_^ ).

That being said, as a piece of anecdotal information, compared to my 5D MarkIII using Magic Lantern RAW video, the BMCC had more dynamic range and offered a cleaner image up to ASA800.


Edited by Vladimir Cazacu, 17 October 2017 - 05:54 PM.

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#7 Evan Richards

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Posted 17 October 2017 - 05:58 PM

Now, not to be rude or anything but your question doesn't really make sense, seeing as how the dynamic range of "Canon RAW CR2 files" differs from camera model to camera model

Very true. I have a 5D mk II so those are the files I'm used to working with.

 

So, when you say 1600 is just 800 with 1EV gain, does that mean it's no different than adding the gain in post? I've read something like that but didn't know if it was true. Because if that WERE the case, there would never be any reason to change your ISO from 800.

 

Good to know about the 5d mk III raw. I'll bet the mark II and mark III CR2 files have more dynamic range than the magic lantern raw.


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#8 Vladimir Cazacu

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Posted 17 October 2017 - 06:00 PM

So, when you say 1600 is just 800 with 1EV gain, does that mean it's no different than adding the gain in post? I've read something like that but didn't know if it was true. Because if that WERE the case, there would never be any reason to change your ISO from 800.

 

 

Pretty much.


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#9 Tyler Purcell

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Posted 17 October 2017 - 11:20 PM

Which is why I specifically asked about raw stills in the title and body of my post.


Sure, but the CR2 files are actually raw imager files, rather than compressed moving image files. Plus you're dealing with A LOT MORE DATA with CR2 then Cinema DNG. So it's really hard to compare them.

Actually it would be a folder full of DNG files.


Which are actually Tiff files. They put a different extension on them, but in the end all they are is a compressed Tiff file.

Red Code is just JPEG2000 for instance.

They are similar because they are both raw image file formats that can both be opened and manipulated with adobe camera raw. I was asking about the comparison in dynamic range which should be an easy correlation to make.


When you're dealing with 12 bit or higher RAW files, which capture images pre-bayer, you're now down to the imager, rather than the codec.

The Canon imager is designed specifically for RAW capture, that's where it shines the most.

The Blackmagic imagers are designed for built-in Bayer encoding and Pro Res capture in LOG mode. Cinema DNG doesn't quite work as well from my experience as Pro Res HQ does, even using DaVinci to color.

In the long run, you can't compare the two at all, it's not apple to oranges... it's pineapples to milk. WAY too many variables.

What ya need to know is in that graph above, even though I disagree with it quite a bit. I shoot at 200 a lot and it's FAR MORE then 2 stops of latitude in the mid range.
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#10 Daniel Meier

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Posted 18 October 2017 - 09:58 AM

Interesting thread. I'm also a BMPCC owner, but didn't quite yet figure out exposing the camera with iso settings other than ISO 800.

I tested all ISO settings from 200 to 1600 in RAW mode. I realized that at 1600 there was a bit more highlight detail (about 0,5 to 1 stop). Of course there was also more noise and the danger of seeing fixed pattern noise in certain situations.

ISO 200 and 400 were really gross looking in terms of highlight detail. My theory (also read it on BMCuser) is, that in RAW mode the camera always peforms at its native ISO 800. So if you change your ISO to 200, you now feed the sensor with 2 stops more exposure through the lens. But since the camera is still set at 800 you overexpose the image and lose highlight detail. I guess it's something like Pulling and Pushing with film. Just in a crappy digital way. So changing to 200 will do the same as putting a -2 EV LUT on the display. Similar to Sony Slog2 LUTs, where you deliberately want to overwxpose the image.


Here are some questions that still leave me being confused about the BMPCC:

1. The Camera is said to have 13 stops of DR. In which shooting mode does that apply (RAW and/or ProRes). At which Iso setting?

2. Since my test with different ISO settings I'm quite in doubt, that the above mentioned gray tone mapping also applies to the BMPCC.
Lower ISO were definitely not giving me more shadow detail. Just less noise

3. So far I haven't seen anyone complaining about thr green tint the camera has. It can't be fixed with simple Tint slider controls. It only affects some parts of the image (especially the midtones) in some lighting conditions (mostly sun and overcast daylight). I found the Slog2 Lut for Sony's A7s2 applied to Prores BMD footage giving me thr most neutral looking colors. No one adresses this issue and no one uses this Lut.

Maybe you guys can share some knowledge / experience. Would appreciate it.
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#11 Vladimir Cazacu

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Posted 18 October 2017 - 10:30 AM

 

 

In RAW mode the camera always peforms at its native ISO 800. So if you change your ISO to 200, you now feed the sensor with 2 stops more exposure through the lens. But since the camera is still set at 800 you overexpose the image and lose highlight detail. I guess it's something like Pulling and Pushing with film. Just in a crappy digital way. So changing to 200 will do the same as putting a -2 EV LUT on the display. Similar to Sony Slog2 LUTs, where you deliberately want to overwxpose the image.

 

 

 

 

That is exactly how it works, as the ISO information is just metadata baked into the CinemaDNG files.

The sensor is always running at ASA800 but the image you get will be different depending on how much light you expose the sensor to:

 

- if you expose for ASA400, you get a cleaner image because of the fact that you are pushing the noise floor down one stop but you also lose -1eV of highlight information

 

 

Here are some questions that still leave me being confused about the BMPCC:

1. The Camera is said to have 13 stops of DR. In which shooting mode does that apply (RAW and/or ProRes). At which Iso setting?

 

It always has 13 stops of DR (though how many of the ones in the shadows are "usable" is another thing) but the ratio of stops above/below middle grey shifts depending on how much light you are exposing the sensor to (look at the graph above, it's the key to understanding how to expose BMD cameras). 

 

3. So far I haven't seen anyone complaining about thr green tint the camera has. It can't be fixed with simple Tint slider controls. It only affects some parts of the image (especially the midtones) in some lighting conditions (mostly sun and overcast daylight). I found the Slog2 Lut for Sony's A7s2 applied to Prores BMD footage giving me thr most neutral looking colors. No one adresses this issue and no one uses this Lut.

I can't really say that my BMPCC or BMMCC had a huge green tint but the in camera color matrix is quite far from being true to life.

 

Are you using an IR/UV cut filter with your camera or maybe a cheap ND filter?

 

 


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#12 Tyler Purcell

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Posted 18 October 2017 - 01:57 PM

I found the Slog2 Lut for Sony's A7s2 applied to Prores BMD footage giving me thr most neutral looking colors. No one adresses this issue and no one uses this Lut.


Yea never seen that problem before. The only "issues" I get are related to IR pollution, but there is a fix for that via an OPLF you can install. I just haven't invested yet because it's expensive for how cheap the camera is.

I always record in LOG mode with my BMPCC and use DaVinci's "Blackmagic Cinema V2" LUT as my base. I found it to deliver exactly what the camera was seeing on location. Then I make minor corrections from there to fix whatever is wrong.

I also shoot A LOT at 200iso, I'd say "most" of the time. Protecting highlights is a huge problem in this mode, but when you're shooting exterior day, even with filtration, it's critical because the camera is so damn sensitive.

Here is a camera test I did a while ago with the Zeiss 12-120 at 200 ISO with only a LUT applied, no other corrections.

https://www.dropbox....12-120.mov?dl=0
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#13 Daniel Meier

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Posted 19 October 2017 - 06:33 AM

Thanks Tyler and Vlad for sharing your knowledge. Here are two sample frames from a Prores BMPCC shot to illustrate my green-tint-issue.

 

https://www.dropbox....09 (2).jpg?dl=0

https://www.dropbox....UT (2).jpg?dl=0

 

https://www.dropbox....9 (12).jpg?dl=0

https://www.dropbox....T (12).jpg?dl=0

 

I named the files according to the LUTs I've been applying to those shots. (No grading, just the LUTs being put on).

As you can see the Boz BMD Film LUT has more green in the neutral parts of the image (mostly the mid-gray sections), whereas the EOSHD SLOG2 LUT results in a far more pleasing, neutral looking image. All of the usual BMPCC-REC709 LUTs give me that ugly green tint, just like the BOZBMDFilm LUT.

This occurs in both situations, with and without any ND filtration. I even get better results with some heavier NDs (e.g. an ND 1.8), since it has a little magenta shift to it.

 

I also did test the Hoya IR Cut filter, which gets hyped to death by every BMPCC user.

I returned it after one day of testing, since I thought it was way overpriced for the effect it does. It fixes an issue that might just as well be removed in the grading process.

I ordered the Rawlite OLPF yesterday, which also includes an IR Cut filter. But my main goal is to shoot RAW with less moiré. (Since RAW is way more prone to moirè than ProRes is on the Pocket).


Edited by Daniel Meier, 19 October 2017 - 06:36 AM.

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#14 Tyler Purcell

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Posted 19 October 2017 - 12:49 PM

Looks like green in the midtones to me. Interesting, I'll have to mess around with the Sony LUT's. I have tried dozens of other LUT's but none of them give me the proper color reproduction.

The material above isn't very saturated, to me I go after saturation in a LUT first. Then I work on tweaking by hand.
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#15 Ethan Alexander

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Posted 20 October 2017 - 12:52 PM

It's interesting because if I'm reading this right, this chart would seem to indicate it would be best practice to shoot at 1600 ASA in brighter light because you'd get more latitude in your brighter areas.

 

 

Since it's an EI chart, you'd always be shooting at 800 (native) but exposing for 1600, which would mean you're stopping down or adding more ND, therefore protecting your highlights and giving you that increased DR above middle grey.  This is different than selecting 1600 in the camera, which will give you less DR and more noise.

 

DR will always be greatest at native, but where the stops fall (above or below middle grey) is up to how you rate the ISO for exposure.


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