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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 :)

Dragon Vs Alexa Low Light Tests - Someone?

not so sure if Alexa RAW is 16bit, in the codex age, it was/is 12bit, log colorspace, uncompressed bayer files
in their doc : http://www.arri.com/camera/digital_cameras/workflow/working_with_arriraw/arriraw/format/

you can also check this if you have a frame and look at the filesize : in 4:3 modus
2880x2160x 12bit = 74649600 bits, or 9331200 kbyte/frame = 9,3MB
http://www.arri.com/camera/digital_...ng_with_arriraw/recording/alexa_xt_xr_module/

if it was 16bit,
2880x2160x 16bit = 99532800 bits or 12441600 kbyte/frame = 12,4MB/frame if it were 16Bit

ofcourse because of the logspace recording, you could say at can capture a '16bit linear colorspace '
-- if not in logspace you could only record 12stops in 12bits data by definition...
 
It was 12 at release, as far as my memory serves me…

May have grown. But there are multiple ways they could go beyond 12 stops, like doing dual readouts at different voltage and averaging that into a single image, etc…

hey… Does that not sound like something I hard about the Alexa :)
 
Gunleik Groven said:
My wish for 2014:

Let somehow people understand that the only thing that affects "exposure" and noise, is the number of photons hitting the sensor.

ISO (on RED cameras) does not alter the noise or "cleanness"/Fidelity of an image. You can rate it at "any" ISO and get identical results when you develop from "any" ISO.

You cannot change the amount of light you used in post, though…

There is no magic involved. Just physics...
Click to expand...

+1

Further ... when shooting - you can (sometimes) change the lighting and you can (almost always) change the aperture. You can use NDs or a Motion Mount to reduce photons hitting the sensor if/when controlling your depth of field via aperture/focal length is your creative priority.

The relevance of how you rate the ISO - all depends on what tools and methodology a person is using to choose their aperture.

I've got a bit more testing to do this week but so far ... IMO ... false color in RAW is by far the best on-camera tool for exposure on Dragon.
 
Gunleik Groven said:
My wish for 2014:

Let somehow people understand that the only thing that affects "exposure" and noise, is the number of photons hitting the sensor.

ISO (on RED cameras) does not alter the noise or "cleanness"/Fidelity of an image. You can rate it at "any" ISO and get identical results when you develop from "any" ISO.

You cannot change the amount of light you used in post, though…

There is no magic involved. Just physics...
Click to expand...

I'm glad someone pointed this out. ISO is pure metadata, and has absolutely zero affect on how much light is hitting the sensor. The amount of light hitting the sensor is the ONLY thing that affects CLIPPING on a RED MX or Dragon sensor. This is pretty much DAY 1 of RED 101 folks!
 
Mark L. Pederson said:
I've got a bit more testing to do this week but so far ... IMO ... false color in RAW is by far the best on-camera tool for exposure on Dragon.
Click to expand...

That's something new for Dragon, right? Like on MX, I thought false colour was based off the histogram, which is metadata/not raw sensor values… Or are you saying you monitor it in "raw" (the hold-over from R1 days) and then turn on false colour based on that? If that's the case, doesn't it require boatloads more light (in effect, lighting for ISO250-320, and then exposing for ISO800, which should always work anyway.)
 
Mike P. said:
That's something new for Dragon, right? Like on MX, I thought false colour was based off the histogram, which is metadata/not raw sensor values… Or are you saying you monitor it in "raw" (the hold-over from R1 days) and then turn on false colour based on that? If that's the case, doesn't it require boatloads more light (in effect, lighting for ISO250-320, and then exposing for ISO800, which should always work anyway.)
Click to expand...

Monitor in RAW mode. Lemme confirm some more tests and circle back to this. But false color in RAW mode it is NOT "in effect, ISO 250-320" on Dragon.
 
G,

You've said this quite a few times and alas, it makes sense to me and you might get your wish for 2014, at least from one soul and I will spread this knowledge, once I have mastered it.

Examples for further clarification:

Shoot at dark scene at 300 ISO or 2000 ISO, what determines the cleanness of the image or level of noise is how you set your aperture and shutter speed to let light onto the sensor. Push the ISO all you want, the noise is in essence "FIXED," by your aperture.

Advise:

How to shoot a dark scene out in the field without light?

By this same logic, any dark scene with little light is going to have noise, no matter what...
Change the ISO all you want, even use Super Speeds. If you shoot in the dark, you are shooting in the noise floor, this is unavoidable...?

To say picking up noise in a dark image is "unavoidable" is sad. At what point do you give the sensor enough light? A match, a torch. The failing light at dusk isn't enough? When are we going to have a camera with "What you see is what you get." Shoot blacks, let them be black. Not black with noise.

Now there is something about me that cannot accept this, that will push this camera, test it in the dark and find a way to achieve my low light goals.

In the old film days, recording black capture an image with black being black, no dancing artifacts or noise?

Gunleik Groven said:
My wish for 2014:

Let somehow people understand that the only thing that affects "exposure" and noise, is the number of photons hitting the sensor.

ISO (on RED cameras) does not alter the noise or "cleanness"/Fidelity of an image. You can rate it at "any" ISO and get identical results when you develop from "any" ISO.

You cannot change the amount of light you used in post, though…

There is no magic involved. Just physics...
Click to expand...
 
Will Keir said:
When are we going to have a camera with "What you see is what you get." Shoot blacks, let them be black. Not black with noise.

Now there is something about me that cannot accept this, that will push this camera, test it in the dark and find a way to achieve my low light goals.

In the old film days, recording black capture an image with black being black, no dancing artifacts or noise?
Click to expand...

a) Dragon many times will see MORE than you see.

b) You want to crush the blacks in post - essentially grading the noise floor to black

c) In the old film days - black was not always black - depended on the lab - and there was often plenty of dancing grain :)
 
Will Keir said:
Advise:

How to shoot a dark scene out in the field without light?

By this same logic, any dark scene with little light is going to have noise, no matter what...
Change the ISO all you want, even use Super Speeds. If you shoot in the dark, you are shooting in the noise floor, this is unavoidable...?

To say picking up noise in a dark image is "unavoidable" is sad. At what point do you give the sensor enough light? A match, a torch. The failing light at dusk isn't enough? When are we going to have a camera with "What you see is what you get." Shoot blacks, let them be black. Not black with noise.

Now there is something about me that cannot accept this, that will push this camera, test it in the dark and find a way to achieve my low light goals.

In the old film days, recording black capture an image with black being black, no dancing artifacts or noise?
Click to expand...


I'll jump in on this.

The fundamentals behind all cameras is their ability to see light and capture it. If there's no light, nothing in the world is going to help you record an image. If you are in a dark field without light and you mean truly without light no amount of sensitivity or image gain will help really.

If you are trying to mimic you're eye in very dark situations, well that's a whole different thing. But even our eyes have a "max" when it comes to low light, even after adapting to those conditions. Some cinematographers opt to go to a 360 degree shutter to produce a low light aesthetic which also gains you one stop if you're using typical capture practices with a 180 degree shutter.

The concept itself is sort of similar across all capture systems. As Mark said black isn't always black with film, nor clean. In fact "milky blacks" were an interesting problem that often resulted in "lifting" the film past it's own "noise floor". There' simply nothing there at some point.

My advice is when shooting darkness, make it black like Mark said. Underworld is a good example of a dark film shot on Red with good tonal separation between the environment and black leather coats of the actors. They achieved this look however using light. Without it you have nothing.
 
Phil Holland said:
They achieved this look however using light. Without it you have nothing.
Click to expand...

And on that note, I will just greet all my RedUser Friends.

Exposure and contrast = use of light and lighting in one way or another, even when in a dark scene and with "available" lights.

1. To get good blacks, you need light.
2. Exposure = the photons that actually hit the sensor.
3. Photo Graphy = Painting With Light

Cinematography 101 2013 is thus done for my part.

Happy new year everyone!
May we all make good images and films in 2014!

Cheers!

And a huge shout to Phil for all the stuff he has done to make RedUser a much better place to be again over 2013.

Cheers and happy celebrations!

G
 
Eyes are 'grainy' as well

Eyes are 'grainy' as well

I'll add this: even our human eyes have plenty of noise and grain. Just look around in a really dark room and see what the 'grain' looks like, it's interesting if you look at it from a camera persons perspective .
I might add that I was amused that it really looks rather filmic in it's texture quality, something like 16mm :-)

Having said that, lower noise is always better. To me the ideal viewing experience in a theater would be having a completely noiseless image, that when it goes dark like at night , your eyes actually fill in the grain just like in real life. No fake patina of noise needed thank you very much. I still look forward to a non-flinching comparison test of new sensors vs MX. Currently my observation is that Dragon is about a half a stop less noisy, but plenty of great resolution and range available so it's a worthy upgrade.
 
Happy New Year Gunleik and all RedUsers!
 
Gunleik Groven said:
Cinematography 101 2013 is thus done for my part.

Happy new year everyone!
May we all make good images and films in 2014!

Cheers!

And a huge shout to Phil for all the stuff he has done to make RedUser a much better place to be again over 2013.

Cheers and happy celebrations!
Click to expand...

Cheers Gunleik! Here's to a big 2014. I know mine needs to be!
 
Will Keir said:
Advise:

How to shoot a dark scene out in the field without light?

By this same logic, any dark scene with little light is going to have noise, no matter what...
Change the ISO all you want, even use Super Speeds. If you shoot in the dark, you are shooting in the noise floor, this is unavoidable...?

To say picking up noise in a dark image is "unavoidable" is sad. At what point do you give the sensor enough light? A match, a torch. The failing light at dusk isn't enough? When are we going to have a camera with "What you see is what you get." Shoot blacks, let them be black. Not black with noise.

Now there is something about me that cannot accept this, that will push this camera, test it in the dark and find a way to achieve my low light goals.

In the old film days, recording black capture an image with black being black, no dancing artifacts or noise?
Click to expand...

Will…


Basically the "gloom" you describe is correct… :)

But it is not "bad".

People shoot at "ISO 4000" with "good" and "bad" results. What differentiate the results, mostly, is not ISO or if the scene is "really really dark", but if there is not CONTRAST in the scene to attenuate the things you want to attenuate…

Now you say "see like we do". Well, a camera does not. Our vision is pretty limited compared to a cameras, but our brain is over-capable of "filling in the blanks" to make sense of what we see. Thus - mostly, we do not actually see the things we think we "see". Our focus is very narrow, as is our color sight. BUT our brains are very good at attenuating contrast and motion. The most of the rest is not really something we see, but "perception".

THUS
That is a really bad analogy for a camera.

(but a real chest of gold for illusionists)

Now, as cinematographers, our trick is to make people see what we want them to see and make that feel "natural" (or surprising at times)
We are the illusionists who control the viewers sight, if we do our job properly.
we make people see the well exposed faces, and not the underexposed darks. And with just a little bit of contrast, contours and painting, the noise "is not there". Our eyes follow motion and contrast, not low contrast mud, more easily (unless we teach ourself to pixel peep. Which is good, but not necessarily the "end to all" in storytelling)

If you REALLY want those blacks to be technically noise free, you have a few options. All can be pretty hard, but the easiest would be to overexpose them to higher precision and pull them back in post. That would look super smooth.

The more practical approach would be to make sure that the subject you want to give focus, gets focus. That means contrast.

If you start to play with it, it is silly how little attention you have to take to make a scene "pop" and appear noiseless, compared to all the time you can spend in post digging noise up from the mud and then try to denies it.

If there is relevant info for the viewer to see, noise is the last thing that comes to attention.

Now. This sounds maybe like I am pulling the camera vendors "off the hook".
Not at all.

But the cameras and photography are tools and skills.
You "do" something to "make" an image. Even if you just hit the record button. You (consciously or unconsciously) decided to make exactly THAT image.
And if THAT image is not what you are looking for, maybe you should rearrange.

Bringing in super speeds and shooting at 1.3 at 360 degrees will lift the whole scene. Maybe enough.

Moving the camera or the subject or a practical (like a candle or a 12k HMI, depending on the scene) a few inches, may sometimes be the "right" measure.

If you look at Phil and Marks match examples, the striking thing is how well the Dragon reacts to just a little contrast. It is beautiful.

it is not about how the camera lights the scene for you.

And by that…
There is 10 minutes left of my 2013.

See you al next year.

(Phils aswer is as good as mine, BTW… : )
 
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