Low-light sensor issue?

The place for questions about shooting with Blackmagic Cameras.
  • Author
  • Message
Offline
User avatar

adamroberts

  • Posts: 4513
  • Joined: Wed Aug 22, 2012 5:27 am
  • Location: England, UK

Re: Low-light sensor issue?

PostMon Jan 21, 2013 10:02 pm

The camera was picking up more than my eyes could see but personally I think that is far to little light to be shooting under. I would never shoot under those conditions and expect good clean images. Not even with the FS100.

If I had to shoot a wide establishing shot of a city skyline then I'd shoot it earlier in the evening when there was still some light in the sky. You can always pull that back in post for a darker moody shot.

There are limits to how far you can push things.
Offline

Kholi Hicks

  • Posts: 703
  • Joined: Wed Aug 22, 2012 10:23 pm

Re: Low-light sensor issue?

PostMon Jan 21, 2013 10:06 pm

Agreed. I just wouldn't do it, either.

In the case of the street lamp footage, the camera picked up mostly what I saw but with the right amount of noise I would expect. The better thing would've been to use a faster lens (0.95's I know you're reading this!) but it wasn't so bad.

Can't wait for MFT and SLR 0.95's, man.
Kholi Hicks
Offline
User avatar

Tom

  • Posts: 1626
  • Joined: Wed Aug 22, 2012 5:08 am
  • Location: Manchester, UK

Re: Low-light sensor issue?

PostMon Jan 21, 2013 10:37 pm

So Kohli and Adam, what is your opinion on whether this is a legitimate fault or simply a demonstration on the limitations of the camera? Or however you would describe your stance....
Tom Majerski
http://tetragrade.com/
http://www.imdb.com/name/nm5157752/
Offline

Dennis Nomer

  • Posts: 113
  • Joined: Fri Aug 24, 2012 11:54 pm

Re: Low-light sensor issue?

PostMon Jan 21, 2013 11:07 pm

Thanks, Adam, for the DNG's. In spite of the histograms of the shots being (deliberately) way the heck down there, even looking at the DNG's at full size on a nice monitor, I cannot see the kind of line I have seen elsewhere. So in spite of the fact that the sensor is split into a top and bottom, with separate readout circuits, it looks pretty seamless to me. I also like the pattern of the noise, compared to most I have seen. If my surmise is correct, you can read about the technology involved in getting the high DR, and how it 'might' have a difference between the top and bottom halves of the sensor here:

http://www.andor.com/learning-academy/d ... amic-range

But looking at your samples, they look nice to me.

dn
Dennis Nomer
Offline

Kholi Hicks

  • Posts: 703
  • Joined: Wed Aug 22, 2012 10:23 pm

Re: Low-light sensor issue?

PostTue Jan 22, 2013 5:01 am

Tom wrote:So Kohli and Adam, what is your opinion on whether this is a legitimate fault or simply a demonstration on the limitations of the camera? Or however you would describe your stance....


I think this is a good question.

Right now, I would likely go with the latter. But, I think it's a demonstration of the limitations of any camera that's considered RAW. Each one will have its own unique trait apart from FPN. If part of Blackmagic's trait is a bisecting line when grossly underexposed, then your answer is a demonstration of the limitations of this specific unit.

Unlike an FS100 etc, you aren't afforded the in-camera fine-tuning for lowlight and the outbound process of compression to get rid of "blemishes", if that makes sense.

You will have to turn toward more light or a faster aperture to get what you need, or post manipulation (noise reduction, half-frame exposure adjustment).

I imagine that someone some time soon will decide to put two cameras together, one that apparently does not show the same line and one that does, and compare. Likely, both have the same thing in the same exact situations, and the differences we see in DNGs are unique to each specific situation.

That's what this phase is for, testing and reporting.
Kholi Hicks
Offline
User avatar

Christian Schmeer

  • Posts: 904
  • Joined: Sat Sep 29, 2012 5:07 pm
  • Location: London, UK

Re: Low-light sensor issue?

PostTue Jan 22, 2013 5:11 am

I have received a reply from BMD's Technical Support Consultant:

Could you please send me some of the original DNG files that show the issue, as I am going to inspect these with some members of the engineering team, to look closely at this.

Could you also put the lens cap on using the same settings as those two images, and send the DNG files to me also.

Many cameras experience this noise in low light, and sending through the DNG files will help us establish some further information about this.


I will shoot some more low light footage in the next few days and will post them here, as well as send them to BMD. Also, we could do what's suggested: put the lens cap on and take a DNG at the same settings, then see if there are any differences.

Looking at Adam's DNGs, it would really seem that the issue only happens in certain lighting situations. I cannot see the "line" or blue tinted noise in the bottom half of the images, except for the shots of the person.
Christian Schmeer - DP / Colourist
www.christianschmeer.com
www.vimeo.com/christianschmeer
Offline
User avatar

adamroberts

  • Posts: 4513
  • Joined: Wed Aug 22, 2012 5:27 am
  • Location: England, UK

Re: Low-light sensor issue?

PostTue Jan 22, 2013 8:20 am

Tom wrote:So Kohli and Adam, what is your opinion on whether this is a legitimate fault or simply a demonstration on the limitations of the camera? Or however you would describe your stance....


My feeling is similar to Kohli. We have got used to compressed footage that has a lot of in camera processing. That processing and compression masks alot of the sensor issues under extreme conditions.

If you add more like to the scene the issue disappears. To me that says we was pushing the sensor to a place it's not designed to be used.

It does appear that some sensors are more prone to this issue and that needs to be investigated by BMD. They can only do that with our help. So contacting support and supplying test footage is important.
Offline
User avatar

Frank Glencairn

  • Posts: 1658
  • Joined: Wed Aug 22, 2012 7:07 am
  • Location: Germany

Re: Low-light sensor issue?

PostTue Jan 22, 2013 8:47 am

I have no idea what you guys do.

I did several lowlight tests and was pretty happy, how they looked.




and also a BMC vs FS100 test:



As I said, the BMC is a low light camera, but not a no light camera.
If you underexpose a FS100 (known as the queen of the night) you see the same problems, even if Sony's processing voodoo tries, to turn everything into a soft blob at some point.

If you don't overdo it, and bring in some lights when levels are too low, everything is fine.
Just think of the days, when you shot film (if you ever did) and how those scenes your try to shoot unlit now with the BMC, would have looked on film. Even on KODAK VISION3 200T if pushed.
With all the digital cinema, folks seem to have forgotten what film looks in real low light scenarios (not a well lit set, pulled back in post).

Maybe we should all step back a bit and think of the treat we have here with a native 800 ISO camera, instead trying to make it a night vision device.

end of my ct2

Frank
http://frankglencairn.wordpress.com/

I told you so :-)
Offline
User avatar

adamroberts

  • Posts: 4513
  • Joined: Wed Aug 22, 2012 5:27 am
  • Location: England, UK

Re: Low-light sensor issue?

PostTue Jan 22, 2013 9:03 am

I agree Frank.

I think that this issue has come to light because images have been seriously under exposed and so the sensor has little to create an image with.

As I said before I would not expect a clean image, even from the "queen of the night", under those conditions.
Offline
User avatar

Tom

  • Posts: 1626
  • Joined: Wed Aug 22, 2012 5:08 am
  • Location: Manchester, UK

Re: Low-light sensor issue?

PostTue Jan 22, 2013 1:14 pm

Frank Glencairn wrote:I have no idea what you guys do.

I did several lowlight tests and was pretty happy, how they looked.




and also a BMC vs FS100 test:



As I said, the BMC is a low light camera, but not a no light camera.
If you underexpose a FS100 (known as the queen of the night) you see the same problems, even if Sony's processing voodoo tries, to turn everything into a soft blob at some point.

If you don't overdo it, and bring in some lights when levels are too low, everything is fine.
Just think of the days, when you shot film (if you ever did) and how those scenes your try to shoot unlit now with the BMC, would have looked on film. Even on KODAK VISION3 200T if pushed.
With all the digital cinema, folks seem to have forgotten what film looks in real low light scenarios (not a well lit set, pulled back in post).

Maybe we should all step back a bit and think of the treat we have here with a native 800 ISO camera, instead trying to make it a night vision device.

end of my ct2

Frank


I also agree Frank, I share your stance also.

My contribution to this thread is more to try and help to explore whether this is an inherent characteristic of the camera or a fault with selected models. I have made my personal perception of the problem clear, but continue to try and objectively explore the various possibilities.

I do not intend to shoot using as little light as appears to be necessary to bring out this problem.
Tom Majerski
http://tetragrade.com/
http://www.imdb.com/name/nm5157752/
Offline
User avatar

Frank Glencairn

  • Posts: 1658
  • Joined: Wed Aug 22, 2012 7:07 am
  • Location: Germany

Re: Low-light sensor issue?

PostTue Jan 22, 2013 2:19 pm

This sounds like a mantra, and I said it many time before:

Treat the Cinema Camera like a cinema camera (cinema as in film) - but @ 800 ISO and the lab in your computer - and you are golden.
http://frankglencairn.wordpress.com/

I told you so :-)
Offline
User avatar

JorgeDeSilva

  • Posts: 91
  • Joined: Fri Aug 31, 2012 9:38 pm
  • Location: Switzerland | Portugal

Re: Low-light sensor issue?

PostTue Jan 22, 2013 4:11 pm

I have some interesting results from 2 days shooting with the camera, lowlight in the city.
A lot of persons will become disappointed, just saying!
Not in every situations, because in another situations these things can happen ( :) !!! ) :

Image

Full review soon :)
Jorge De Silva - Photography & Filmmaking
http://www.imdb.com/name/nm1843499/
Offline
User avatar

rick.lang

  • Posts: 13392
  • Joined: Wed Aug 22, 2012 5:41 pm
  • Location: Victoria BC Canada

Re: Low-light sensor issue?

PostTue Jan 22, 2013 9:56 pm

JorgeDeSilva wrote:I have some interesting results from 2 days shooting with the camera, lowlight in the city.
A lot of persons will become disappointed, just saying!
Not in every situations, because in another situations these things can happen ( :) !!! ) :

Image

Full review soon :)


Jorge, do you have the time to tell us the exposure you were shooting for that city night shot? Don't know how dim your street is but we have seen other city night shots that looked vastly better than this. Thanks.

Rick Lang
Sent from my iPad using Tapatalk HD
Rick Lang
Offline
User avatar

Christian Schmeer

  • Posts: 904
  • Joined: Sat Sep 29, 2012 5:07 pm
  • Location: London, UK

Re: Low-light sensor issue?

PostTue Jan 22, 2013 10:04 pm

rick.lang wrote:Don't know how dim your street is but we have seen other city night shots that looked vastly better than this.


What's wrong with that shot? Looks pretty good to me. Although...the frame is scaled down, so it's impossible to see any noise.
Christian Schmeer - DP / Colourist
www.christianschmeer.com
www.vimeo.com/christianschmeer
Offline
User avatar

rick.lang

  • Posts: 13392
  • Joined: Wed Aug 22, 2012 5:41 pm
  • Location: Victoria BC Canada

Re: Low-light sensor issue?

PostTue Jan 22, 2013 10:26 pm

Christian Schmeer wrote:
rick.lang wrote:Don't know how dim your street is but we have seen other city night shots that looked vastly better than this.


What's wrong with that shot? Looks pretty good to me. Although...the frame is scaled down, so it's impossible to see any noise.


Christian, perhaps I did not read Jorge's comment correctly but I thought he said many would be disappointed by his low light shots. Wasn't this shot supposed to illustrate that? Looking at it on the iPad4 (2048x1536), it seemed to have more noise than other city night shots that we have seen. Let's wait for Jorge's detailed review.

Rick Lang
Sent from my iPad using Tapatalk HD
Rick Lang
Offline

Dennis Nomer

  • Posts: 113
  • Joined: Fri Aug 24, 2012 11:54 pm

Re: Low-light sensor issue?

PostWed Jan 23, 2013 8:48 am

The actual resolution of that image posted by Jorge is only 700 x 394. If you look at a blow-up (by an iPad), then that is not a good measure. We would all agree DNG's are best for evaluating quality.

To me, just roughly, I can see into all of those dark places that no one is lighting very well. I have seen all sorts of TV episodic, and even film work where the night shots (if actually shot at night) are thoroughly crushed in all of those dark areas. This camera pulls them out pretty well, with no one exerting any effort to light anything. I have seen crews, even on ultra low budget junk flicks spend significant money on a crane-mounted big light to try to put just some light into a dark street over a wide area for a shot. It seems to me that a lot of people on this forum want to do absolutely nothing in the way of lighting and still call themselves a DP. Man!
Dennis Nomer
Offline
User avatar

JorgeDeSilva

  • Posts: 91
  • Joined: Fri Aug 31, 2012 9:38 pm
  • Location: Switzerland | Portugal

Re: Low-light sensor issue?

PostWed Jan 23, 2013 8:53 am

Hello Rick. That is not a bad example of bad light really.... If you read my comment.
I'm just saying... I'm a lot disappointed... I will wait for the MFT to have more fast lenses...
I'm gonna try to have the full review ready for the end of the week, with DNG samples incluided.

Thanks,
J
Jorge De Silva - Photography & Filmmaking
http://www.imdb.com/name/nm1843499/
Offline
User avatar

JorgeDeSilva

  • Posts: 91
  • Joined: Fri Aug 31, 2012 9:38 pm
  • Location: Switzerland | Portugal

Re: Low-light sensor issue?

PostWed Jan 23, 2013 8:58 am

DNomer wrote:The actual resolution of that image posted by Jorge is only 700 x 394. If you look at a blow-up (by an iPad), then that is not a good measure. We would all agree DNG's are best for evaluating quality.

To me, just roughly, I can see into all of those dark places that no one is lighting very well. I have seen all sorts of TV episodic, and even film work where the night shots (if actually shot at night) are thoroughly crushed in all of those dark areas. This camera pulls them out pretty well, with no one exerting any effort to light anything. I have seen crews, even on ultra low budget junk flicks spend significant money on a crane-mounted big light to try to put just some light into a dark street over a wide area for a shot. It seems to me that a lot of people on this forum want to do absolutely nothing in the way of lighting and still call themselves a DP. Man!


Correct. My test is fully with no light. To test the sensor of the camera. BMCC can not be comparable to another cameras like DSLR and FS100 etc. It's way worse in lowlight, "WAY" in a big way, without proper lighting.
So again, the only way to get good results with the BMCC is to treat it like a REAL cinema camera. Lighting is the key!
Jorge De Silva - Photography & Filmmaking
http://www.imdb.com/name/nm1843499/
Offline

Felix Steinhardt

  • Posts: 205
  • Joined: Sat Aug 25, 2012 9:45 pm
  • Location: Karlsruhe / Germany

Re: Low-light sensor issue?

PostWed Jan 23, 2013 11:06 am

That´s weird! I´ve seen good low light footage and heard people saying it´s doing a very descent job in low light. I wonder if those sensors have a high series deviation -> one clean, another noisy as hell.
Offline

John Brawley

  • Posts: 2361
  • Joined: Tue Aug 21, 2012 7:57 am
  • Location: London UK

Re: Low-light sensor issue?

PostWed Jan 23, 2013 2:10 pm

I think it's more to do with expectations.

In the last couple of years only, Canon mainly and now the sony's have allowed us to shoot in ridiculously high ISO numbers.

This camera has a top ISO of 1600.

The C300 is 24000 and it's useable to 12000 or so. That's a big difference.

If you want to shoot in low / no light, this probably isn't your camera.

jb
John Brawley
Cinematographer
London UK
Offline

jeffthechef

  • Posts: 2
  • Joined: Wed Jan 23, 2013 2:03 pm

Re: Low-light sensor issue?

PostWed Jan 23, 2013 2:11 pm

So here's my issue, pretty new to this camera got hooked up and him shooting a talking head with the camera in a totally dark area the subject is in a lighted room but the camera is in the area that is dark. I have the Rokinon 24mm F1.4 lens and the camera set the video, ProRez and I can't seem to get proper color. I'm wearing a bright red shirt with a yellow happy face on it in the shirt looks rust in the yellow looks more tan. Any ideas on how to help?

I have to admit that I'm not really a cinematographer I'm more a video engineer plan to build this rig.
Offline
User avatar

adamroberts

  • Posts: 4513
  • Joined: Wed Aug 22, 2012 5:27 am
  • Location: England, UK

Re: Low-light sensor issue?

PostWed Jan 23, 2013 2:44 pm

jeffthechef wrote:I'm wearing a bright red shirt with a yellow happy face on it in the shirt looks rust in the yellow looks more tan. Any ideas on how to help?


What White Balance have you se the camera to and what colour is your lighting?
Offline
User avatar

JorgeDeSilva

  • Posts: 91
  • Joined: Fri Aug 31, 2012 9:38 pm
  • Location: Switzerland | Portugal

Re: Low-light sensor issue?

PostWed Jan 23, 2013 3:52 pm

John Brawley wrote:I think it's more to do with expectations.

In the last couple of years only, Canon mainly and now the sony's have allowed us to shoot in ridiculously high ISO numbers.

This camera has a top ISO of 1600.

The C300 is 24000 and it's useable to 12000 or so. That's a big difference.

If you want to shoot in low / no light, this probably isn't your camera.

jb



Yes and No JB. The thing is, with this camera you really need to do proper exposure (feed the sensor, as I read on your blog).
My making of footage with my nex5n at ISO1600 18-55 lens at f/3.5, have more light, better color, better DR that the real scene shooted with the BMCC with a 28mm lens at f2.8 at ISO 1600 (in RAW does not really matter).
I have recorded to film gamma (raw option), and the preview to film gamma too (my big mistake). In the screen I see everything, all the details... but the DNG is BLACK, like BLACK!
I had to push more that 2 EV and the image became really BAD.... :/ ... so... for me... night with bmcc only with proper lighting. But that's ok... because that was my test of the camera, and not a real shoot!
I'm gonna have a full week soon only to concentrate and shoot with the bmcc, after that I will bring my new results, now that I know the quirks of the camera.

Best,
JDS


P.s: JB... just like we talk yesterday... It took me 2h to export a couple of minutes of DNG... OUCH!
Good news is, that in a couple of weeks i receive my workstation :) Resolve FTW!
Jorge De Silva - Photography & Filmmaking
http://www.imdb.com/name/nm1843499/
Offline
User avatar

rick.lang

  • Posts: 13392
  • Joined: Wed Aug 22, 2012 5:41 pm
  • Location: Victoria BC Canada

Re: Low-light sensor issue?

PostWed Jan 23, 2013 5:53 pm

DNomer wrote:The actual resolution of that image posted by Jorge is only 700 x 394. If you look at a blow-up (by an iPad), then that is not a good measure. We would all agree DNG's are best for evaluating quality.


Agreed! When using the iPad, it just fills the screen when you double-tap so I had assumed it was a HD image; so my bad. I don't know how to query the image size on iOS on the iPad as there's no control, option, command keys.

Rick Lang
Sent from my iPad using Tapatalk HD
Rick Lang
Offline

Kholi Hicks

  • Posts: 703
  • Joined: Wed Aug 22, 2012 10:23 pm

Re: Low-light sensor issue?

PostWed Jan 23, 2013 6:27 pm

Felix Steinhardt wrote:That´s weird! I´ve seen good low light footage and heard people saying it´s doing a very descent job in low light. I wonder if those sensors have a high series deviation -> one clean, another noisy as hell.


Inexperience, limited experience, relativity.

Those are the primary reasons. You'll notice that the people saying that it's decent in lowlight are also pretty experienced, and put out some decent "tests". Like John says, if you're trying to get FS100 no light results out of it, this isn't the camera for you.
Kholi Hicks
Offline
User avatar

JorgeDeSilva

  • Posts: 91
  • Joined: Fri Aug 31, 2012 9:38 pm
  • Location: Switzerland | Portugal

Re: Low-light sensor issue?

PostWed Jan 23, 2013 7:21 pm

Kholi wrote:
Felix Steinhardt wrote:That´s weird! I´ve seen good low light footage and heard people saying it´s doing a very descent job in low light. I wonder if those sensors have a high series deviation -> one clean, another noisy as hell.


Inexperience, limited experience, relativity.

Those are the primary reasons. You'll notice that the people saying that it's decent in lowlight are also pretty experienced, and put out some decent "tests". Like John says, if you're trying to get FS100 no light results out of it, this isn't the camera for you.


Kholi I had told a couple of times... that my tests would be with NO lights at all!
I really have pushed the camera to the limits (even with the sh*tty LCD preview), because I wanted to know what that sensor can do.
In a production environment we need lighting. But we need to remember the major target for this camera... DSLR owners...! So yes... if the people want to do lowlight footage like Canon DSLR ans Sony FS... It's better to forget the BMCC!

I'm already editing the backtage with DNG samples too. Soon :)
Jorge De Silva - Photography & Filmmaking
http://www.imdb.com/name/nm1843499/
Offline

Kholi Hicks

  • Posts: 703
  • Joined: Wed Aug 22, 2012 10:23 pm

Re: Low-light sensor issue?

PostWed Jan 23, 2013 8:07 pm

JorgeDeSilva wrote:
Kholi I had told a couple of times... that my tests would be with NO lights at all!
I really have pushed the camera to the limits (even with the sh*tty LCD preview), because I wanted to know what that sensor can do.
In a production environment we need lighting. But we need to remember the major target for this camera... DSLR owners...! So yes... if the people want to do lowlight footage like Canon DSLR ans Sony FS... It's better to forget the BMCC!

I'm already editing the backtage with DNG samples too. Soon :)


The problem is that there isn't a camera out there that can do what you're trying to make it do in a RAW form. Not one. There's no benefit of noise reduction in camera or in the compression chain. You kind of don't have to "push the camera to the limits" to know that if you've worked with similar... it's not a Canon DSLR (which are all terrible in no-light, anyway) or an FS100... you have to do the work, the camera doesn't do it for you.

=P I'm not trying to be unpleasant or mean, I guess it's just going to be a very steep learning curve for many.
Kholi Hicks
Offline
User avatar

JorgeDeSilva

  • Posts: 91
  • Joined: Fri Aug 31, 2012 9:38 pm
  • Location: Switzerland | Portugal

Re: Low-light sensor issue?

PostWed Jan 23, 2013 8:13 pm

Kholi wrote:
JorgeDeSilva wrote:
Kholi I had told a couple of times... that my tests would be with NO lights at all!
I really have pushed the camera to the limits (even with the sh*tty LCD preview), because I wanted to know what that sensor can do.
In a production environment we need lighting. But we need to remember the major target for this camera... DSLR owners...! So yes... if the people want to do lowlight footage like Canon DSLR ans Sony FS... It's better to forget the BMCC!

I'm already editing the backtage with DNG samples too. Soon :)


The problem is that there isn't a camera out there that can do what you're trying to make it do in a RAW form. Not one. There's no benefit of noise reduction in camera or in the compression chain. You kind of don't have to "push the camera to the limits" to know that if you've worked with similar... it's not a Canon DSLR (which are all terrible in no-light, anyway) or an FS100... you have to do the work, the camera doesn't do it for you.

=P I'm not trying to be unpleasant or mean, I guess it's just going to be a very steep learning curve for many.


No, I agree with you. But noise and bad exposure is a thing, what I HAVE it's way different. It's a really steeping curve. My next shoot I will have all that details now in my head.
Jorge De Silva - Photography & Filmmaking
http://www.imdb.com/name/nm1843499/
Offline

John Brawley

  • Posts: 2361
  • Joined: Tue Aug 21, 2012 7:57 am
  • Location: London UK

Re: Low-light sensor issue?

PostWed Jan 23, 2013 8:20 pm

JorgeDeSilva wrote:

Yes and No JB. The thing is, with this camera you really need to do proper exposure (feed the sensor, as I read on your blog).
My making of footage with my nex5n at ISO1600 18-55 lens at f/3.5, have more light, better color, better DR that the real scene shooted with the BMCC with a 28mm lens at f2.8 at ISO 1600 (in RAW does not really matter).
I have recorded to film gamma (raw option), and the preview to film gamma too (my big mistake). In the screen I see everything, all the details... but the DNG is BLACK, like BLACK!


Jorge a couple of things.

You can recreate what you saw on your screen when shooting film mode in resolve. You won't like it though because it's LOG. And nothing looks good in LOG. But, if you want what you had there, then you can just go to the DNG tab and choose "BMD FILM"

When I talk about feeding the sensor more light, the reason we do this is noise, not sensitivity.

The more ETTR we are, the more away from noise we are. What's unusual about the BMCC is that you can expose even more ETTR than you can with other cameras.

Google ETTR and you'll see the background to why we do this.

The camera has a certain sensitivity. You saw the image when looking at your screen in LOG. You can have that image in post. The screen isn't showing you something that you can't get.

But like I said, you're probably going to find there is no colour, the blacks are lifted to mid grey...a LOG image.

I still say that at 1600 the camera is a good performer. You'll still have a high dynamic range image and some noise.

JB.
John Brawley
Cinematographer
London UK
Offline
User avatar

JorgeDeSilva

  • Posts: 91
  • Joined: Fri Aug 31, 2012 9:38 pm
  • Location: Switzerland | Portugal

Re: Low-light sensor issue?

PostWed Jan 23, 2013 8:24 pm

John Brawley wrote:
JorgeDeSilva wrote:

Yes and No JB. The thing is, with this camera you really need to do proper exposure (feed the sensor, as I read on your blog).
My making of footage with my nex5n at ISO1600 18-55 lens at f/3.5, have more light, better color, better DR that the real scene shooted with the BMCC with a 28mm lens at f2.8 at ISO 1600 (in RAW does not really matter).
I have recorded to film gamma (raw option), and the preview to film gamma too (my big mistake). In the screen I see everything, all the details... but the DNG is BLACK, like BLACK!


Jorge a couple of things.

You can recreate what you saw on your screen when shooting film mode in resolve. You won't like it though because it's LOG. And nothing looks good in LOG. But, if you want what you had there, then you can just go to the DNG tab and choose "BMD FILM"

When I talk about feeding the sensor more light, the reason we do this is noise, not sensitivity.

The more ETTR we are, the more away from noise we are. What's unusual about the BMCC is that you can expose even more ETTR than you can with other cameras.

Google ETTR and you'll see the background to why we do this.

The camera has a certain sensitivity. You saw the image when looking at your screen in LOG. You can have that image in post. The screen isn't showing you something that you can't get.

But like I said, you're probably going to find there is no colour, the blacks are lifted to mid grey...a LOG image.

I still say that at 1600 the camera is a good performer. You'll still have a high dynamic range image and some noise.

JB.


Maybe the reason of not using resolve yet? In adobe I cant have that :/
Jorge De Silva - Photography & Filmmaking
http://www.imdb.com/name/nm1843499/
Offline
User avatar

JorgeDeSilva

  • Posts: 91
  • Joined: Fri Aug 31, 2012 9:38 pm
  • Location: Switzerland | Portugal

Re: Low-light sensor issue?

PostWed Jan 23, 2013 8:37 pm

So, just to understand (and I really appreciate the help and hints here).

Here is it. This is all the available light that I had on the street (nex5n Iso1600 18-55 f/3.5):
Image

Image


This is the BMCC (28mm lens at F/2.8):
Image

With 2EV more:
Image

I have some shooted with a 50mm at F/1.4. Just a little bit better...

I know that for a real production Lighting is the key. But i just expect more... Next time I need faster lenses and expose more (to the right i know :) I use RAW in photograhy ;) )
Jorge De Silva - Photography & Filmmaking
http://www.imdb.com/name/nm1843499/
Offline
User avatar

Brian T

  • Posts: 14
  • Joined: Wed Aug 22, 2012 4:39 am

Re: Low-light sensor issue?

PostWed Jan 23, 2013 9:04 pm

Jorge, what color profile did you use to film that with (Video or Film)?
If Film it looks like you've crushed the blacks way to much in post.
In any event it doesn't give the camera justice. I've shot in the same [if not lower light] and I've had much better footage.
Offline
User avatar

Tom

  • Posts: 1626
  • Joined: Wed Aug 22, 2012 5:08 am
  • Location: Manchester, UK

Re: Low-light sensor issue?

PostWed Jan 23, 2013 9:05 pm

Jorge, would you please share a DNG of that shot with us please.
Tom Majerski
http://tetragrade.com/
http://www.imdb.com/name/nm5157752/
Offline
User avatar

JorgeDeSilva

  • Posts: 91
  • Joined: Fri Aug 31, 2012 9:38 pm
  • Location: Switzerland | Portugal

Re: Low-light sensor issue?

PostWed Jan 23, 2013 9:10 pm

Brian T wrote:Jorge, what color profile did you use to film that with (Video or Film)?
If Film it looks like you've crushed the blacks way to much in post.
In any event it doesn't give the camera justice. I've shot in the same [if not lower light] and I've had much better footage.


No post here. direct from the camera. Fim Gamma in the BMCC.
Jorge De Silva - Photography & Filmmaking
http://www.imdb.com/name/nm1843499/
Offline
User avatar

JorgeDeSilva

  • Posts: 91
  • Joined: Fri Aug 31, 2012 9:38 pm
  • Location: Switzerland | Portugal

Re: Low-light sensor issue?

PostWed Jan 23, 2013 9:18 pm

Tom wrote:Jorge, would you please share a DNG of that shot with us please.


Yup: https://www.dropbox.com/s/swh9sm3ji3ydg ... 000265.dng


Just to say, not everything is bad! I love the camera! I will create a BMCC experience thread soon :) With lovely samples!
Jorge De Silva - Photography & Filmmaking
http://www.imdb.com/name/nm1843499/
Offline
User avatar

Tom

  • Posts: 1626
  • Joined: Wed Aug 22, 2012 5:08 am
  • Location: Manchester, UK

Re: Low-light sensor issue?

PostWed Jan 23, 2013 10:13 pm

Thanks for the dng.


here it is in BMCFilm mode within Davinci resolve. Untouched, no grading.

ScreenHunter_15 Jan. 23 22.04.jpg
ScreenHunter_15 Jan. 23 22.04.jpg (57.27 KiB) Viewed 11300 times



This would be how it looked on the bmcc lcd screen when set to film mode.
Tom Majerski
http://tetragrade.com/
http://www.imdb.com/name/nm5157752/
Offline
User avatar

JorgeDeSilva

  • Posts: 91
  • Joined: Fri Aug 31, 2012 9:38 pm
  • Location: Switzerland | Portugal

Re: Low-light sensor issue?

PostWed Jan 23, 2013 10:25 pm

Slowly I'm getting there. I'm now trying to push a lot of files above 2EV and using Neatvideo in AFX I'm getting pretty good results. Let's see...


Tom can um push it? and do a small noise reduction? just to have an idea.

Thanks,
JDS
Jorge De Silva - Photography & Filmmaking
http://www.imdb.com/name/nm1843499/
Offline
User avatar

Noel Sterrett

  • Posts: 411
  • Joined: Wed Aug 22, 2012 9:12 pm

Re: Low-light sensor issue?

PostWed Jan 23, 2013 11:23 pm

When you use a full frame lens on the BMCC, it is similar to using a lens doubler on a FF camera - it costs you in terms of exposure.

The effective crop factor of the BMCC is 2.4 and the effective T-stop loss is 2.4 stops.

That's one of the great features of the Metabones Speedbooster. It increases the effective stop by the factor that the focal length is decreased: 1.4. It is still less that it would be at FF, but much closer.

An MFT lens would have less exposure loss, as the sensor area it covers is much closer to the BMCC.

Cheers.
Admit One Pictures
Ubuntu 20.04 | Asus Z10 Xeon*2 32G | GTX 1080 8G | Resolve Studio 16 | Desktop Video 11
Offline

Felix Steinhardt

  • Posts: 205
  • Joined: Sat Aug 25, 2012 9:45 pm
  • Location: Karlsruhe / Germany

Re: Low-light sensor issue?

PostWed Jan 23, 2013 11:25 pm

Hmm, that´s really a bit dark compared to the Sony Cam. Was the Shutter angle set correctly?
I wouldn´t expect that ISO 800 is so dark compared to ISO 1600

@Noel: That´s just not correct. F1.4 is F1.4 no matter how big or small your sensor is.
Attachments
darklinger.jpg
darklinger.jpg (331.39 KiB) Viewed 11278 times
Offline
User avatar

adamroberts

  • Posts: 4513
  • Joined: Wed Aug 22, 2012 5:27 am
  • Location: England, UK

Re: Low-light sensor issue?

PostThu Jan 24, 2013 1:04 am

With so little light there is not a lot of detail left in the DNG.

00086400.jpg
00086400.jpg (849.5 KiB) Viewed 11265 times
Offline

CaptainHook

Blackmagic Design

  • Posts: 1678
  • Joined: Wed Aug 22, 2012 4:50 am
  • Location: Melbourne, Australia
  • Real Name: Hook

Re: Low-light sensor issue?

PostThu Jan 24, 2013 3:17 am

Based on those nex5 images being F3.5@iso1600, i have trouble believing that BMCC DNG is at F2.8. It's at least 4 stops under (i tried it with BMDFilm and pushed it to 4.0 - even there i would think it needed more light/exposure). Are you sure there wasn't an ND filter on you didn't notice? Haha.

Frank's night/dark exposures definitely don't seem like this.. but of course that means nothing without knowing the conditions etc they were shot and yours.
**Any post by me prior to Aug 2014 was before i started working for Blackmagic**
Offline

Kholi Hicks

  • Posts: 703
  • Joined: Wed Aug 22, 2012 10:23 pm

Re: Low-light sensor issue?

PostThu Jan 24, 2013 3:23 am

Agreed with Cap'n Hook, AND I was going to ask about the ND filter as well! lol But not having been there we definitely have to take it on word.

Wish I had my camera... seems like every day there's something else I want to test, haha.

But, you can look at Frank Glencairn's FS100 test from months ago and extrapolate from there.
Kholi Hicks
Offline
User avatar

JorgeDeSilva

  • Posts: 91
  • Joined: Fri Aug 31, 2012 9:38 pm
  • Location: Switzerland | Portugal

Re: Low-light sensor issue?

PostThu Jan 24, 2013 8:05 am

Noel Sterrett wrote:When you use a full frame lens on the BMCC, it is similar to using a lens doubler on a FF camera - it costs you in terms of exposure.

The effective crop factor of the BMCC is 2.4 and the effective T-stop loss is 2.4 stops.

That's one of the great features of the Metabones Speedbooster. It increases the effective stop by the factor that the focal length is decreased: 1.4. It is still less that it would be at FF, but much closer.

An MFT lens would have less exposure loss, as the sensor area it covers is much closer to the BMCC.

Cheers.


No. A lens never changes the F/value!

The intensity of light at the centre of the image (i.e. photons per square inch) on the smaller sensor has not changed, so the exposure is not affected. Yoo can lost some light by having a smaller image circle, but that is light that would not have hit the sensor anyway.

So apertures and f/stop values do not change between sensor sizes!
Jorge De Silva - Photography & Filmmaking
http://www.imdb.com/name/nm1843499/
Offline
User avatar

JorgeDeSilva

  • Posts: 91
  • Joined: Fri Aug 31, 2012 9:38 pm
  • Location: Switzerland | Portugal

Re: Low-light sensor issue?

PostThu Jan 24, 2013 8:12 am

Felix Steinhardt wrote:Hmm, that´s really a bit dark compared to the Sony Cam. Was the Shutter angle set correctly?
I wouldn´t expect that ISO 800 is so dark compared to ISO 1600

@Noel: That´s just not correct. F1.4 is F1.4 no matter how big or small your sensor is.



Yes felix. 180 degrees. I have recorded at ISO 1600 on the BMCC (but in raw doesn't matter)
Jorge De Silva - Photography & Filmmaking
http://www.imdb.com/name/nm1843499/
Offline
User avatar

JorgeDeSilva

  • Posts: 91
  • Joined: Fri Aug 31, 2012 9:38 pm
  • Location: Switzerland | Portugal

Re: Low-light sensor issue?

PostThu Jan 24, 2013 8:15 am

CaptainHook wrote:Based on those nex5 images being F3.5@iso1600, i have trouble believing that BMCC DNG is at F2.8. It's at least 4 stops under (i tried it with BMDFilm and pushed it to 4.0 - even there i would think it needed more light/exposure). Are you sure there wasn't an ND filter on you didn't notice? Haha.

Frank's night/dark exposures definitely don't seem like this.. but of course that means nothing without knowing the conditions etc they were shot and yours.


haha That's funny... but I'm not so dumb :P In night shoots NO nd (only in my daylight shoots that I will post soon).

I Will repeat the details: BMC at iso 1600 (RAW is always ISO 800) + m42 Sigma 28mm at F/2.8 - 24 FPS with 180 degree.
Jorge De Silva - Photography & Filmmaking
http://www.imdb.com/name/nm1843499/
Offline
User avatar

JorgeDeSilva

  • Posts: 91
  • Joined: Fri Aug 31, 2012 9:38 pm
  • Location: Switzerland | Portugal

Re: Low-light sensor issue?

PostThu Jan 24, 2013 8:19 am

Kholi wrote:Agreed with Cap'n Hook, AND I was going to ask about the ND filter as well! lol But not having been there we definitely have to take it on word.

Wish I had my camera... seems like every day there's something else I want to test, haha.

But, you can look at Frank Glencairn's FS100 test from months ago and extrapolate from there.


Frank tests had lighting! This test is more "raw" test of the sensor. And in the Frank teste the BMCC it's only good in sharpness to my view...!

I just have learn that it's impossible to shoot with BMCC with the same circumstances as DSLR and Sony FS cameras... Just that! The daylight shoots are a different story! A lot of DR.. The color... The sharpness! :)
Jorge De Silva - Photography & Filmmaking
http://www.imdb.com/name/nm1843499/
Offline
User avatar

JorgeDeSilva

  • Posts: 91
  • Joined: Fri Aug 31, 2012 9:38 pm
  • Location: Switzerland | Portugal

Re: Low-light sensor issue?

PostThu Jan 24, 2013 8:27 am

I'm not the most experienced guy in the field (with raw video). But I deal a lot with red footage for example. And the way you have to expose the BMCC it's simple different. In the BMCC you have to overexpose to feed the sensor, when you are shooting you see the overexposed images in LCD, that sucks! In red it's not the same way, even it's a raw camera too.

It's Not a Defect of bmcc, It's a Feature... :/

Soon I will make more lowlight things, with now this new rules in consideration. And I will have a red one to the party... let's see...


Best,
J
Jorge De Silva - Photography & Filmmaking
http://www.imdb.com/name/nm1843499/
Offline

John Brawley

  • Posts: 2361
  • Joined: Tue Aug 21, 2012 7:57 am
  • Location: London UK

Re: Low-light sensor issue?

PostThu Jan 24, 2013 11:47 am

I think for a TRUE test Jorge we need to see the same frame pointing at the same scene at the same time at the same exposure.

If you own the two cameras, it should be easy for you to do.

I'm not at home or I'd upload some, but I've done plenty of walking around in available light with this camera. You should be getting better than this.

jb
John Brawley
Cinematographer
London UK
Offline

John Brawley

  • Posts: 2361
  • Joined: Tue Aug 21, 2012 7:57 am
  • Location: London UK

Re: Low-light sensor issue?

PostThu Jan 24, 2013 11:48 am

JorgeDeSilva wrote: In the BMCC you have to overexpose to feed the sensor, when you are shooting you see the overexposed images in LCD, that sucks! In red it's not the same way, even it's a raw camera too.

I


When shooting RAW, this is when you use the ISO function. Set it to ISO200 and your bright screen won't be so bright.

jb
John Brawley
Cinematographer
London UK
Offline

Felix Steinhardt

  • Posts: 205
  • Joined: Sat Aug 25, 2012 9:45 pm
  • Location: Karlsruhe / Germany

Re: Low-light sensor issue?

PostThu Jan 24, 2013 12:39 pm

I just watched Franks lowlight test again. RAW does seem to be a lot darker than prores.


Watch:
0:17 Min FS100 ISO 800
0:54 Min BMCC Proes ISO 800 ( a little darker than the FS100)
2:02 Min BMCC RAW -> Really dark. More like ISO 200 compared to the FS100.

Maybe setting the screen to ISO 400 is a better idea when recording RAW.
PreviousNext

Return to Cinematography

Who is online

Users browsing this forum: Brad Hurley, Chris Gosling, MONNYS and 36 guests