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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 :)

How many stops do you need?

M

Michael Brennan

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Following on from the NOX cam thread, what do we think is the next best combination of fstop range of sensor, A/D and recording output?
We can all wish for 20 stops on the sensor but in reality what do we use on a day to day basis?

My suggestion for TV work is
14 stop imager
16 bit A/D
12 bit recording


Not too many circumstances where TV work needs more than 14 stops?

No doubt that one day there will be near unlimited contrast range that will make film look naff and poly boards redundant.

Mike
 
Just to cover everything 16 bit gives you film like flexibility.
One way to do it on the 12 bit CMOS sensor is to read the CMOS twice for each frame.
First time for shades and the second time for highlights, with 4 bit light level offset.
Alternatively one could install two sensors with the splitter and combine the two 12 bit signals in to the 16 bit, with 4 bit offset. 4 bit offset have to be also implemented as a light intensity offset entering these two CMOS sensors. (4 stops light difference gathered by these two CMOS sensors)
Sure CMOS technology is improving so one day we may see 16 bit Misterium out there.
 
Mickjoebill said:
Not too many circumstances where TV work needs more than 14 stops?


Mike
Click to expand...

Hi Mike,

You are joking? Unless you are shooting on film you have no chance of being near 14 stops.

I think many TV shows are so flatly lit that a 4 stop sensor would do!

Stephen
 
Agreed.

However, field EPK ENG EFP etc. for broadcast is another matter.
National geographic in the Sahara, Contiki in the middle of the Pacific..no control here.

J.
 
Stephen Williams said:
Hi Mike,

You are joking? Unless you are shooting on film you have no chance of being near 14 stops.

I think many TV shows are so flatly lit that a 4 stop sensor would do!

Stephen
Click to expand...

I think you are looking at the wrong TV shows. Try use a 4 stop sensor to capture Rome, The Black Donnollys, Lost, Supernatural, Battlestar Gallactica or Heroes and you are greatly lacking.

Now the average three camera sitcom has to be lit nasty flat so the image can be adequate from anywhere inside a 110 degree arc... and that isn't pretty.

It is considered a single camera show but quite often Jon Casser is getting Rodney Charters to light '24' so that two or three cameras can capture simultaneously and still look good. That can't be easy.
 
Dalsa's sensor is 16 bit. They claim more than 12 stops, but it doesn't give a specific number. According to what others have said, if I'm understanding correctly, it's theoretically capable of 16-stops of linear response. Then factor in s/n ratio to find what's usable within those 16 stops. Am I correct in this assumption?
Deanan from Dalsa is with RED now, so maybe we will see a 16-bit upgrade in a few years, if the other architechture would support that. But, in any case, 12 bits and 11-12 stops is still fantastic and I've been very happy with the images that I've seen so far. I feel a bit silly speculating on the next generation when the first isn't even here yet. So, I'll shut up now.
 
CMOS technology will not do much more then 12 bit for now in terms of S/N ratio.
Dalsa is CCD Bayer sensor so it may go stop or two farther but it is in expense of speed. 30fps max.

CCD have to push speed or CMOS have to reduce the noise.
 
>Dalsa is CCD Bayer sensor so it may go stop or two farther but it is in expense of speed.<

gotcha. thanks.
 
I want 23 stops and a 64bit color space. And yes I could use it well maybe not the color space but with a little redcine like application I would be perfectly content to have it lock in the histogram to the alpha channel and as it starts to any color range begin to transition into alpha.
 
im.thatoneguy said:
I want 23 stops and a 64bit color space. And yes I could use it...
Click to expand...
Have you worked with any cameras offering 23 stops of dynamic range? What lens did you use? I am curious because it is my impression that surface and bulk scattering effects from even the best lenses available would limit the performance to something less than 23 stops, regardless of how good the sensor is. Maybe you can do better with entirely reflective optics which are kept in a cleanroom, or in space vacuum.
 
im.thatoneguy is of course joking. Not even film will do 23 stops. I believe film will be around 14 stops max, if that. And not every emulsion. So, no worries...a sensor with anywhere above 11-12 stops will be fine for most applications.
 
With 23 stops you could film the sun being sucked into black hole.
 
how 'bout a quasar....:tongue:
 
Clint Johnson said:
I think you are looking at the wrong TV shows. Try use a 4 stop sensor to capture Rome, The Black Donnollys, Lost, Supernatural, Battlestar Gallactica or Heroes and you are greatly lacking.

Now the average three camera sitcom has to be lit nasty flat so the image can be adequate from anywhere inside a 110 degree arc... and that isn't pretty.

It is considered a single camera show but quite often Jon Casser is getting Rodney Charters to light '24' so that two or three cameras can capture simultaneously and still look good. That can't be easy.
Click to expand...

Of course the ultimate limitation is the dynamic range reproduction capabilities of the TV transmission and display technologies. It's a vast understatement to say that TV isn't currently capable of displaying anything approaching 14 stops. And digital cable is often so compressed that the images often look like moving abstract paintings with blobs of pixels shifting around the screen.
 
When I first started doing FX work, and was using the frontlight/backlight process for stop motion, you only had to light your screen to about three stops over medium grey for solid white and you found three stops under was good black.... this was with good old 5247.

Everything (film and digital) has come a long way...

Hey, I still have a can of '47 in the freezer... anyone want to buy it? Probably has an effective ASA of 5 now, with grain the size of paint splatter...
 
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