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Viper News


Derek Schweickart

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Because things seem to be moving so fast in the world of digital I want to start a thread here to put news about the Viper system. For me this includes necessarily news about the S-Two recording device.

 

As many of you know, Thomson has announced their onboard flash RAM recording device called the "Venom". Check out the official page for more info. http://www.thomsongrassvalley.com/products/cameras/venom/

For me this has been a large missing link in this stage of digital cinematography, so onboard recording of uncompressed Viper log images is a huge deal.

 

S-Two has developped a button box for the DFR so that laptop control is no longer necessary. For those of you interested in more information about S-Two, I will do my best to respond in the "S-Two" thread.

 

Another sidenote, the Camera House has made a deal of physical add-ons to the Viper including a power breakout box (24 volt Fischer 2-pin to 2 x 24V Fischer 3-pin and 2 x 12V Fischer 11-pin), onboard battery (24V), handheld base plate top, studio base plate top, and a series of modular quick release shoes to quickly organize and rearrange your accessories (Onboard monitor, Lens Control, Arri style carrying handle, etc.). These were all much needed modifications and they enable the camera to function much more readily as a hand-held camera. Combined with the Venom, you will find the Viper a much changed system come Summertime when Venom becomes available for use.

 

Derek Schweickart

 

Digital Tech

The Camera House

7351 Fulton ave.

North Hollywood CA 91605

818 997 3802

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Can the Viper record to an HDCAM-SR deck in FilmStream mode? If not, how does one backup the S2 recorders to a tape based medium to satisfy the insurance companies?

 

Also, when shooting in 2.40 mode does the camera have a built in de-amorphoser (sp?) for proper aspect-ratio viewing on the monitor?

Edited by Starway2001
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Can the Viper record to an HDCAM-SR deck in FilmStream mode?  If not, how does one backup the S2 recorders to a tape based medium to satisfy the insurance companies?

 

Also, when shooting in 2.40 mode does the camera have a built in de-amorphoser (sp?) for proper aspect-ratio viewing on the monitor?

 

Yes, the Viper can record to the SRW-1 or SRW-5000 in filmstream mode. It is still 10bit information so even though the signal undergoes a logarithmic conversion you're still dealing with the same bit depth.

S2 has a tape backup system called an A-Dock combined with a Scalar LTO2 (soon to be LTO3) data tape jukebox. The LT0 format is made by Fuji and is an approved deliverable format. It is widely used for data backup by banks and insurance companies and many other institutions dealing with data archiving. The good thing about data tape is that it is cheap and lightweight, like video tape, but is still uncompressed. Also, LTO readers are cheap. I think HP makes one for a couple grand.

 

When shooting in 2:37 mode, the Viper does not output a squeezed image on the viewing port, but it does squeeze the viewfinder image. The S-Two DFR has a built in squeeze to output a corrected image for viewing on all of its outputs. The only real problem is if the operator wants to use a monitor instead of the eyepiece. It would require a video feed back from the DFR. Realistically though, if this is the case, a second cable could be taped (or snaked) with the mulitcore cable from the camera since it has to be there anyway.

 

Hope this helped.

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  • 3 weeks later...
Yes, the Viper can record to the SRW-1 or SRW-5000 in filmstream mode. It is still 10bit information so even though the signal undergoes a logarithmic conversion you're still dealing with the same bit depth.

S2 has a tape backup system called an A-Dock combined with a Scalar LTO2 (soon to be LTO3) data tape jukebox. The LT0 format is made by Fuji and is an approved deliverable format. It is widely used for data backup by banks and insurance companies and many other institutions dealing with data archiving. The good thing about data tape is that it is cheap and lightweight, like video tape, but is still uncompressed. Also, LTO readers are cheap. I think HP makes one for a couple grand.

 

When shooting in 2:37 mode, the Viper does not output a squeezed image on the viewing port, but it does squeeze the viewfinder image. The S-Two DFR has a built in squeeze to output a corrected image for viewing on all of its outputs. The only real problem is if the operator wants to use a monitor instead of the eyepiece. It would require a video feed back from the DFR. Realistically though, if this is the case, a second cable could be taped (or snaked) with the mulitcore cable from the camera since it has to be there anyway.

 

Hope this helped.

 

Does the SRW-1 or SRW-5000 have a squeeze feature? It would be nice if Blackmagic HDLink performed this function as well as the LUT correction.

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Does the SRW-1 or SRW-5000 have a squeeze feature?  It would be nice if Blackmagic HDLink performed this function as well as the LUT correction.

 

 

 

As far as I know, the Sony devices do not. As far as HDlink goes, I have not used that card and do not know that much about it. I can't imagine it would be easy to put LUTs in a hardware device because they need to be flexible and customizable. It's much more of a software concern.

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As far as I know, the Sony devices do not. As far as HDlink goes, I have not used that card and do not know that much about it. I can't imagine it would be easy to put LUTs in a hardware device because they need to be flexible and customizable. It's much more of a software concern.

 

The HDLink box supports LUTs via a hardware/software combo.

 

http://www.blackmagic-design.net/products/hdlink/

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The HDLink box supports LUTs via a hardware/software combo. 

 

http://www.blackmagic-design.net/products/hdlink/

 

Thanks for the info. I'm wondering what you think of the HDlink if you've used it before. I've used Ecinema and AJA DVI converters for viewing but not the Blackmagic.

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  • 2 months later...

Well because the color space is still 4:4:4 RGB, the same as the Sony F950. Filmstream is a mode where all the color processing circuits, matrixes and gamma are turned off and at the same time the signal undergoes a 12 bit to 10 bit logarithmic conversion instead of the normal linear scaling. This results in more exposure latitude and a less noisy image. It also gives you more options as far as what you look you want in post because the image starts out flat and low contrast but has enough bit depth to be able to push it around any which way you may want to go.

In any case, Filmstream really shines when trying to hang on to highlights or pull detail out of the lower tones.

If you have any more questions, feel free to ask.

Derek

 

Hi Derek,

could you explain the difference between filmstream and RGB?

Why call it RGB if it has TV gammas applied?

Mike Brennan

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Well because the color space is still 4:4:4 RGB, the same as the Sony F950. Filmstream is a mode where all the color processing circuits, matrixes and gamma are turned off and at the same time the signal undergoes a 12 bit to 10 bit logarithmic conversion instead of the normal linear scaling. This results in more exposure latitude and a less noisy image. It also gives you more options as far as what you look you want in post because the image starts out flat and low contrast but has enough bit depth to be able to push it around any which way you may want to go.

In any case, Filmstream really shines when trying to hang on to highlights or pull detail out of the lower tones.

If you have any more questions, feel free to ask.

Derek

I don't wan to appear argumentative :) but there are some gaps in the understanding as to why filmstream mode is better.

What is your definition of exposure latitude?

I don't understand why log processing (apparently) gets more highlights out of the 12bit AD than lin.

I mean, the log circuits are processing the same 12bit AD looking at highlights and saturated ccds... Surely the output white point from the AD is constant?

 

And how can log, with its extra steps allocated in the shadows (at the expense of the rest of the picture) pull in more detail from the highlights?

 

 

 

Mike Brennan

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Mike,

 

Yes you're on the right lines.

 

The 10Bit log output just makes better use of the 10 bits of information with respect to where (in the luminance range) the eye is most sensitive. Where the camera is fully saturated (burnt out), the log file will also be at its highest value.

 

So the filmstream output doesn't help with the point at which the camera burns out. What it does help with is that it uses each of the 10 bits in a more meaningful way in terms of what the eye is sensitive to and what it is not. The result of this is that visually speaking (not mathematically speaking) there is more information available for post production grading, because effectively the bits are concentrated in the sensitive areas.

 

Having said that, if the post grading doesn't take the final master miles away from what was shot, there is an argument that the linear output (HD stream) wouldn't cause a great deal of problems but in return, means that you can see a decent image on an external monitor while you are shooting.

 

David Cox

Baraka Post Production

www.baraka.co.uk

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Mike,

 

Yes you're on the right lines.

 

The 10Bit log output just makes better use of the 10 bits of information with respect to where (in the luminance range) the eye is most sensitive. Where the camera is fully saturated (burnt out), the log file will also be at its highest value.

 

So the filmstream output doesn't help with the point at which the camera burns out. ....

David Cox

Baraka Post Production

www.baraka.co.uk

 

Yes, I'm glad soemone sees where I am comming from with this perspective!

What most DPs care about is controlling highlights, we are told that filmstream gives more exposure latitude but in fact their are less steps allocated to defining highlight detail.

Shouldn't this mean that there is less highlight detail... equals less dynamic range?

 

How filmstream can thus be described as having increased latitude is one of the great err mysteries of HD, as I see it !

 

OK so the processing records more tonal steps, more tonality in the shadows to which our eyes are more sensative. However, the shadows are fairly easy to control in TV mode, increase black gamma or add a little light a more practical solution compared to the control needed for highlights...

 

Comments?

 

Mike Brennan

Edited by mike
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Well because the color space is still 4:4:4 RGB, the same as the Sony F950. Filmstream is a mode where all the color processing circuits, matrixes and gamma are turned off and at the same time the signal undergoes a 12 bit to 10 bit logarithmic conversion instead of the normal linear scaling. This results in more exposure latitude and a less noisy image. It also gives you more options as far as what you look you want in post because the image starts out flat and low contrast but has enough bit depth to be able to push it around any which way you may want to go.

In any case, Filmstream really shines when trying to hang on to highlights or pull detail out of the lower tones.

If you have any more questions, feel free to ask.

Derek

 

Derek,

again, I don't want to appear argumentative, but you haven't really explained why 444 rgb with good gammas has less exposure latitude than log.

 

In respect to what is good for post RGB can also deliver "flat" at same bit depth as log ? so where is the advantage of log in post?

 

Mike Brennan

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Mike,

I appreciate the challenge, this is what the forum is about. Unfortunately, I have been out of town lately and haven't been able to address your questions. I intend to do some more reseach to give you a more complete answer, but for the moment I can say that "good gammas" can achieve much of the same effect as the log output but the argument for using log is that it is a constant value and gives you good results without painting the image, and tweaking the gamma settings for each shot. This is a workflow option and is debatable. There is also an argument in favor of shooting log when outputting to film, because you can reliably apply a reverse log function to the signal and recreate an accurate 12 bit linear signal.

Let's continue this debate, I'll see if I can't find some more concrete answers.

Derek

 

 

Derek,

again, I don't want to appear argumentative, but you haven't really explained why 444 rgb with good gammas has less exposure latitude than log.

 

In respect to what is good for post RGB can also deliver "flat" at same bit depth as log ? so where is the advantage of log in post?

 

Mike Brennan

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Hi,

 

> accurate 12 bit linear signal

 

Accurate to what, though? It's only ever accurate to what the CCD output, and that's a function of so many degrees of drive electronics I don't even want to go into it. All you're really talking about here is getting back to some notionally idealised set of numbers which never meant much anyway.

 

I grow more and more impatient with this stuff; it's either "pretty" or "not pretty", or slow or quick to work with!

 

Phil

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Hi,

 

Same with film, it's just that the terms were invented (by the manufacturers) a long time ago. I have a very strong conviction that it shouldn't be the responsibility of manufacturers to "make it look like a film camera" just to please people who can't be bothered to learn new things.

 

Phil

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Well, the simplest and most meaningful way to think about filmstream is to consider that a CCD can only do one thing, it reacts to light. Any gamma, gain or color correction applied does not change how the chip reacts. Why correct the image in camera rather than acquire the most raw data of the light hitting the sensor, and correct it later? I believe the DP would want to acquire the most information about the light in a scene as possible.

If you are very interested in painting the chips on set, then Filmstream is not for you.

As far as the log singal is concerned, Thomson decided it is a better way to use the 12 bit data since they are forced to scale it down to 10 bits. I don't have a definitive answer on the highlight question yet, but yes the white point is the same log or no log, and no, highlight detail does not exactly equate dynamic range.

Anyway, Filmstream allows the DP to shoot as if he were shooting a particular film stock. He knows how it reacts to light and he works with it. It makes for a very fast moving schedule because there is no painting on set, which of course does not make DITs happy, I understand the resistance.

 

It's a good camera, it's light and easy to use, and produces a great picture, and with filmstream you can point, focus and shoot and be sure you're getting as good a picture out of the camera as possible. That's a bit simplisitc but there's the idea.

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I grow more and more impatient with this stuff; it's either "pretty" or "not pretty", or slow or quick to work with!

 

Phil

 

Phil,

 

The viper in Film Stream mode is both "pretty" and quick to work with.

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Hi,

 

Yes, fine, but it doesn't work very much like a film camera and this should not be a frustration for anyone. If it is, get someone else!

 

Also regarding easy workflow I hear many terrifying things about Viper on set and the truckloads of support equipment, although I suspect that a lot of this is unnecessary if you're willing to look at the ungraded image, or a statically graded image, and say "Yeah, fine, that'll be OK."

 

Phil

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Well, the simplest and most meaningful way to think about filmstream is to consider that a CCD can only do one thing, it reacts to light. Any gamma, gain or color correction applied does not change how the chip reacts. Why correct the image in camera rather than acquire the most raw data of the light hitting the sensor, and correct it later? I believe the DP would want to acquire the most information about the light in a scene as possible.

If you are very interested in painting the chips on set, then Filmstream is not for you.

As far as the log singal is concerned, Thomson decided it is a better way to use the 12 bit data since they are forced to scale it down to 10 bits. I don't have a definitive answer on the highlight question yet, but yes the white point is the same log or no log, and no, highlight detail does not exactly equate dynamic range.

Anyway, Filmstream allows the DP to shoot as if he were shooting a particular film stock. He knows how it reacts to light and he works with it. It makes for a very fast moving schedule because there is no painting on set, which of course does not make DITs happy, I understand the resistance.

 

It's a good camera, it's light and easy to use, and produces a great picture, and with filmstream you can point, focus and shoot and be sure you're getting as good a picture out of the camera as possible. That's a bit simplisitc but there's the idea.

 

 

Derek,

In respect of highlights I awaite your research into white point of log vs lin.

 

 

In respect to painting on set I think that shooting with carefull consideration of gammas will give the DP more room to manouver in post, because selecting a gamma in camera gets him closer to where he is going with his look. In addition it also allows a DP to interact his lighting sceme to the location with the benifit of the monitor. (the reason given so far for Filmstream not being used on many movies)

 

Shooting filmstream does not allow a DP to use the camera like any film stock but one!

Using gammas the DP can select his filmstock in camera.

 

Derek, the idea of this thread is to explore other ways of expressing what filmstream does. Repeating manufactures product description has lead to a lot of confusion now 444 rgb with film gammas is available from Sony.

 

Filmstream does not record raw data from ccds, it records a 10 bit log conversion of a 12 bit analouge to digital conversion of the raw data from the ccds!! Phew , thats two prcesses removed from recording RAW data of the ccds!

 

You actually say why not capture the *most* raw data and leave it to post? Because the "the most" raw data from a ccd is actually still being chanelled through the 12bit AD, so the more correct question is what is the best way to record the output from the 12 bit AD?

 

Filmstream gives you a "lets try and capture it all approach", gammas give you the approach of pointing the bus in the right direction and then fine tuning in post.

 

Horses for courses but don't say filmstream records more or captures more without qualification or you are doing the marketing guys work for them!

 

It is simple to use as you say at the cost of reducing the control the DP has of getting the look he wants on location and actually giving him less to work with in post than had he chosen a setup close to what he wanted.

 

 

The fact that for the past 3 years Viper has been delivering green pictures in filmstream mode when optical correction (or correction in the AD) would have given you more room to play with the green channel in post is an example of how misunderstood filmstream technique is and how this industry is often lead by manufactures marketing.

 

 

It would be very good to see a wider choice of film style gammas in the Viper in RGB mode, but Thomson have not done any work on the 12bit AD let alone filmstyle gammas since the camera was introduced.

 

And just to further demonstrate how imperfect the termonology is in some Prosumer DV cameras white balance is done within the AD.

 

 

Mike Brennan

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I have a very strong conviction that it shouldn't be the responsibility of manufacturers to "make it look like a film camera" just to please people who can't be bothered to learn new things.

 

They do want to make it look like a film camera, because they would like to get people who shoot film to use their camera. Makes perfect sense to me to go with a proven concept in that case.

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  • 2 weeks later...

and with filmstream you can point, focus and shoot and be sure you're getting as good a picture out of the camera as possible.

 

The above quote is the bit that needs more explaination.

 

I'd agree with you if we could record all of the output from the 12bitAD without further processing. But we don't/can't. (Next generation cameras will have 14bit ADs)

 

 

You are saying that filmstream delivers more shadow and more highlight detail to tape than a reasonable gamma curve in RGB mode?

 

How about the description below;

Filmstream;

is the 10bit log processing of flat RGB from 12bit AD? log proceesing squeezes as much as this as possible on tape.

 

RGB;

a DP/tech/rental house can select a general gamma, thus narrowing down the areas he wants the most to go to tape. So more bits are used to record to tape the parts of the picture that are needed, rather than try to squeeze everything as with filmstream?

 

Both filmstream and RGB use same white and black point from the AD.

Keeping the white balance in the zone is probably better for grading than recording a green filmstream picture. 30 bit? processing within camera is pretty good to manipulate signal and colour balance.

 

 

Comments anyone?

 

 

Mike Brennan

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  • 4 weeks later...

OK so where are the facts?

How can Viper squeeze 2 stops more (manufacturers claim) of dynamic range more out of a 12bit AD than any other camera...

 

Come on guys alot of you have been spouting off that filmstream is the bees knees....

 

 

Mike Brennan

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