Arri Alexa and Mysterium-X...

[Sarah C.]

@Deanan - ok.. fine.. I know when I've been out classed! Bet though if we ever landed on the same set, I'd set-up-us-the-bomb* in lighting faster than ol' Graeme could whip out his Red One. [giggle]

@Roberto - don't count on it. I've seen it go both ways. It can depend on the type of lighting source, and the actual level of output (sun vs. tungsten for example)

@RobertF - whatsupwiththat????

~s

*all your base are belong to us...

 

[Sanjin Jukic]

Always is good thing to remind yourself on some old classic (film) stuff:

Here is how spot metering of exposure was explained by Kodak (October 1998)

Accurate Exposure with Your Meter >>>

 

[Albert Armes]

Albert
Dr Hans Kiening of ARRI Munich who is a well regarded image analysis specialist (and a really nice guy), has devised a test methodology to determine dynamic range that is available to everyone. The specially designed test chart and analysis software determines "usable" image at highlight clip and noise floor by allowing for measurement of modulation (picture information) at both ends. You can evaluate ISO by rating the camera, performing the test, and evaluating the result with the included software. More info is found here http://www.arri.de/camera/35_mm_digital/dynamic_range_test_charts.html

IMHO Its time we all played on the same playing field once again. Camera manufacturers now have a methodology that is common across all capture mediums, from 1/3"CCD/CMOS to 65mm film.

Michael, now this is where you have to help me out. The densitometer ignores the ambient light as it just measures that little patch. It's not a camera pointing at a chart. But in the next picture we see the spectroradiometer which looks to me as if it's right up against the patch ignoring the ambient light. Can you explain more about if you're ignoring or not any ambient light?

Albert

 

[Deanan]

@Deanan - ok.. fine.. I know when I've been out classed! Bet though if we ever landed on the same set, I'd set-up-us-the-bomb* in lighting faster than ol' Graeme could whip out his Red

No doubt there. Graeme would be sipping his Ardbeg

It sounds like I'm saying he's using a red one but I should have mentioned instead that he's using a very sensitive spectroradiometer.

 

[Carsten Fenstermacher]

IMHO Its time we all played on the same playing field once again. Camera manufacturers now have a methodology that is common across all capture mediums, from 1/3"CCD/CMOS to 65mm film.

It would have been much better if it was created by an independent organization like DSC. Just that it's made by one camera co. means that it'll always be somewhat suspect, no?

Imagine if Sony had created and sold the DRTC?

 

[David Mullen ASC]

I seriously doubt one could design a grey scale chart that somehow skewed the results towards only one manufacturer's camera...

Truth is that any chart can be used to test relative differences between two cameras, it's just that the results would be specific to that chart and the moment in time that the two cameras were pointed at it. Which is informative in its own way, which is why we shoot comparison tests.

The problem comes when you start wanting to publicize the results are being definitive and objective, not relative to anything else, but quantifiable in a way that can be reproduced by anyone else using the same methods. That's when you need a good testing methodology.

Whether this ARRI chart is the final word, who knows, it's just another tool. But we honestly don't need some sort of paranoia being spread that it somehow has been magically engineered to make all non-ARRI cameras perform worse in comparison.

And yes, if Sony had come out with the chart, I'd say the same thing. I don't think Sony engineers are somehow less honest than anyone else's engineers.

 

[Hans Kiening]

Michael, now this is where you have to help me out. The densitometer ignores the ambient light as it just measures that little patch. It's not a camera pointing at a chart. But in the next picture we see the spectroradiometer which looks to me as if it's right up against the patch ignoring the ambient light. Can you explain more about if you're ignoring or not any ambient light?

Albert

I guess it´s the best if I try to answer your very valid question myself. First of all the statement concerning straylight refers to approaches with transparent charts with large illuminated areas, second and that is the real important issue - Densitometers were built to measure optical densities of max 3 (the equivalent of 10 f-stops) beyond that they get horrible inaccurate. The spectroradiometer we are using is accurate up to 20 f-stops and this is more the range we need to certify the chart.

The straylight problem in our approach is minimized by the fact that we are using very small illuminated areas so we get away with the aperture of the radiometer.

 

[David Mullen ASC]

I've been wondering this for a while... so with Red and digital formats, you can record to 12 bit RAW, or whatever else, to get more ability to grade in post. Now with big movie productions shooting film, and then digitally scanning it, do they get the same level of manipulation that shooting digital provides? E.g. can they scan the negatives to get more than just 8 bit jpegs?

As someone who has supervised color-correction of film scans (typically uncompressed 10-bit Cineon Log RGB data), plus a multitude of HD material, and Red material... in terms of the ability to manipulate the image in terms of color & gamma, generally film negatives are easier to work with in digital color-correction simply because the scan holds more information that you can choose to use or discard.

It's not as simplistic as the notion that 12-bit RAW has twelve stops to work with and a 10-bit Log scan has 10 stops to work with. You can put all 14+ stops of DR on a film negative into a scan.

Film also seems to capture a greater range of color tonality though this is a subjective impression on my part in the few cases where I had to match something shot digitally to a scene shot on film. I just had more information to work with on the film scan.

Where digital often allows more digital color-correction manipulation than film scans is in terms of the ability to enlarge/crop/reposition the frame or bring up underexposed areas, in both cases, due to the lack of grain.

But all of that is technical. The reasons why a lot of directors prefer film is that they like the way it looks, it's not a question of what's technically "better", it is an emotional response, an aesthetic response.

I worked with one director who thinks that film is softer than digital, and he likes that, so my way of dealing with that with him is to use light diffusion filters. I can tell him that technically the resolution is the same, but I think the lack of grain is what is throwing him off about digital, he misses that texture. He doesn't like the clarity of digital images. Other directors, they don't like the color of skintones in any digital production they've seen. Others don't like the way that motion is rendered.

Some of these opinions are technically grounded and others are just gut emotional responses that are hard to argue with. But they are the directors so I have to make them happy. I mean, what do you say when a director tells you that he's seen almost every digitally-shot feature out there... and that he doesn't like the way any of them look? It creates a high wall to get over to convince them that they aren't going to be unhappy with the digital photography you will be creating for them.

People here are naturally pro-digital and are up on the latest trends, but that's not necessarily the case with all directors out there. This transition from film to digital for features will not be as neat & clean as some people think it will be. We are talking about an art form here, and artists, and these are highly emotional people who don't always make decisions based on logic and rationality.

 

[Shawn Bannon]

People here are naturally pro-digital and are up on the latest trends, but that's not necessarily the case with all directors out there. This transition from film to digital for features will not be as neat & clean as some people think it will be. We are talking about an art form here, and artists, and these are highly emotional people who don't always make decisions based on logic and rationality.

I totally agree. Perfectly worded.

 

[Graeme Nattress]

I seriously doubt one could design a grey scale chart that somehow skewed the results towards only one manufacturer's camera...

Truth is that any chart can be used to test relative differences between two cameras, it's just that the results would be specific to that chart and the moment in time that the two cameras were pointed at it. Which is informative in its own way, which is why we shoot comparison tests.

The problem comes when you start wanting to publicize the results are being definitive and objective, not relative to anything else, but quantifiable in a way that can be reproduced by anyone else using the same methods. That's when you need a good testing methodology.

Whether this ARRI chart is the final word, who knows, it's just another tool. But we honestly don't need some sort of paranoia being spread that it somehow has been magically engineered to make all non-ARRI cameras perform worse in comparison.

And yes, if Sony had come out with the chart, I'd say the same thing. I don't think Sony engineers are somehow less honest than anyone else's engineers.

That's absolutely it - almost any chart is great in a comparison situation, but if the numbers are to be objective, that's when it gets tricky. That's why I'm asking questions on sensitivity ratings that are based upon a particular scan of a particular Kodak film stock.

I agree that you can't engineer a chart to favour a particular camera system. The way that measurements are done can favour parameters which is why I believe that any measurements should be done on linear light data to remove the effect of gamma curves from the issue.

Graeme

 

[Michael Bravin]

Michael, I'm reading through the link you gave above and I'm puzzled - "To determine the sensitivity of your camera you can simply rate it relative to the film scan." So ISO is relative to film or not? The download explicitly says "Sensitivity is relative to 500 ASA Kodak Vision3 film stock"

Graeme

Graeme

The "reference" is 500 ASA Vision 3 which most DPs who shoot film are familiar with and is a known tested repeatable standard and is therefore a good base reference. Once you guys start using the chart you can compare samples with any cameras and use whatever reference you wish.

 

[Michael Bravin]

Michael, now this is where you have to help me out. The densitometer ignores the ambient light as it just measures that little patch. It's not a camera pointing at a chart. But in the next picture we see the spectroradiometer which looks to me as if it's right up against the patch ignoring the ambient light. Can you explain more about if you're ignoring or not any ambient light?

Albert

Albert
The chart is populated by calibrated film patches used to precisely determine the value of each point of light. The densitometer and spectroradiometer are used to calibrated the patches. Once each patch and therefore each point of light is calibrated you can then compare results from chart to chart. You dont have to do the calibration, this is done before you receive the chart. When you test a camera system you shoot the whole chart which gives you a plot of each point. Ignoring stray and ambient light for an accurate measurements.

 

[Graeme Nattress]

Graeme

The "reference" is 500 ASA Vision 3 which most DPs who shoot film are familiar with and is a known tested repeatable standard and is therefore a good base reference. Once you guys start using the chart you can compare samples with any cameras and use whatever reference you wish.

Ok, this gets us back to the original question on sensitivity - how do you objectively do such a comparison? A linear digital sensor is a very different thing from a film density curve.

My original point is that linear light data is not how we view images, but it is a very good reference point for calculations based on them. You can develop a RAW file in an almost infinite variety of ways, many of which will be very valid (making nice looking images). If you compare different cameras each with a different curve applied then that comparison does not make sense. They should have the very same curve applied and that should be no curve at all - linear light data, and then you can see exactly what is happening. The article that prompted this was adamant that the Alexa was ISO800, but that somehow the M-X is fake pushed ISO800, and my point is that for either camera to make a viewable image at that rating, a development curve must be used and the precise nature of that curve will place mid grey such that in the final image produced a reasonable (a nice looking) image will be created.

And all this gets us back to that there is no definition of ISO for raw data and that our current ideas of sensitivity are all tied up with a gamma curve from when cameras were video cameras and had a very much fixed curve, or film where stocks had an ASA, but were routinely rated by their users at different values and pushed and pulled for the specific look / use they were being put to.

Graeme

 

[Cüneyt Kaya]

Hi michael, glad you are hanging out here and talk lil about Arri.

Ok, we know MX`ed R1`s and the upcoming Epic and Arris are and will be great cams.

i have some Q`s about the Arri.

Imho a digital camera is now a 2-part system.
the cam itself and postproduction.
i know with RED i have redcode to keep the needed storage low, i have RED Rocket™™™ to make dailies in realtime and i have the RED SDK so i know i will have direct access to the RAW files at CC sessions.
(pretty much all Postproduction Companies are in a hurry to smoothen their RED workflows and right now there are workflows for every budget out there)


What are the plans of ARRI relating the Postproduction side?

thanks

 

[Michael Bravin]

It would have been much better if it was created by an independent organization like DSC. Just that it's made by one camera co. means that it'll always be somewhat suspect, no?

Imagine if Sony had created and sold the DRTC?

Carsten

The chart is designed by a very well respected image analysis expert Dr. Hans Kiening, and comes with a complete explanation of the design philosophy methodology and process, which anyone can repeat. It was designed so that ARRI engineers could measure the performance of our sensors and system design. It is now available to the general public for use as well as comment and evaluation. We welcome intelligent, rational discussion about issues someone may have with the methodology. It was designed to be a non-skewed reference that everyone could use and compare and contrast performance of various imaging systems including D21 vs ALEXA. In the past various grey scale charts were used some backlit some front lit some uncalibrated and yet the results were compared. Hans felt that these methodologies were not scientific or repeatable enough and did not give an absolute quantifiable measurement so he designed a methodology. This is not a marketing piece. I think the industry will find it a valuable tool for comparing performance of imaging systems. From HDSLR to 8K UltraHD systems, Film and Digital. After careful evaluation your comments and anyone else's are welcome of course.

 

[Chris Clogg]

Other directors, they don't like the color of skintones in any digital production they've seen.

Sorry if I'm getting off topic to the original thread, but:

Speaking of digital, I actually really don't like the way TV and news-shows look. It almost annoys me, they have these whopping cameras on their shoulder that somehow manage to produce a mediocre image... I'm pretty sure my little canon hv20 could do better... sorry if I'm being harsh lol. I do understand that they don't have time to grade/maximize quality.

Also the look of Soap operas doesn't work for me (not that I'd watch them anyway I guess haha)... what I wonder is if they shot the soap opera with a full 35mm film camera (or Red etc., with all same lighting/set), if it would look better. Better in my terms means something like this:

Soap opera:

"Better" film look:

Although, it probably would make 0 difference to viewership because most people don't care.

A lot of digital looks so great and it's really led me to believe it's about natural light (or fill light light that looks good), with proper framing techniques and then grading right.

 

[Patrick Tresch]

Definition of ISO in a raw world... I just read the wikipedia paper, and it seems that the digital aquisition world should work out other tools to comunicate sensitometry.

http://en.wikipedia.org/wiki/Film_speed#The_ISO_12232:2006_standard

Recommended Exposure Index (REI) could be the way if we want to stick to a simple usable number... or a ratio like Julio Quintana suggested between the clipping point and the first available value of captured (raw) data, and this is not subject to any curves/ gamma nor taste.

???

from Wikipedia:
"For example, a camera sensor may have the following properties: S40:1 = 107, S10:1 = 1688, and Ssat = 49. According to the standard, the camera should report its sensitivity as
ISO 100 (daylight)
ISO speed latitude 50–1600
ISO 100 (SOS, daylight)."



Pat

 

[Michael Bravin]

Hi michael, glad you are hanging out here and talk lil about Arri.

Ok, we know MX`ed R1`s and the upcoming Epic and Arris are and will be great cams.

i have some Q`s about the Arri.

Imho a digital camera is now a 2-part system.
the cam itself and postproduction.
i know with RED i have redcode to keep the needed storage low, i have RED Rocket™™™™™ to make dailies in realtime and i have the RED SDK so i know i will have direct access to the RAW files at CC sessions.
(pretty much all Postproduction Companies are in a hurry to smoothen their RED workflows and right now there are workflows for every budget out there)


What are the plans of ARRI relating the Postproduction side?

thanks

Agreed

This is REDUSER so those discussions would be more appropriate on ARRI user We have a forum at: www.arridigital.com for ALEXA discussions. (BTW We have had ARRIRAW workflow in place for a couple of years).

This thread started about a test done with RED MX vs ALEXA so thats how I showed up, and then it morphed into measuring ISO and DR which applies to our industry in general, so I stayed because I love this stuff!

What I will say without offending too many people here, I hope, is that your question will be answered April 6th at the DGA in Hollywood, as we have promised for quite a while, and we plan on delivering camera systems with this workflow in place, in June, as promised.

 

[Roberto Lequeux]

Time to plug your forum but not to respond to the linear light point Graeme is making Michael?

BTW, would you agree that M-X should be: "basically rated at 320 ASA (or more like 200 ASA practically, as many DPs told me)"?

 

[Michael Bravin]

Time to plug your forum but not to respond to the linear light point Graeme is making Michael?

BTW, would you agree that M-X should be: "basically rated at 320 ASA (or more like 200 ASA practically, as many DPs told me)"?

Roberto

Of course I was here merely to "plug" our forum and to side step Graeme's assertion. I am part of the evil troll cabal that stalks on line discussion groups. Beware of the psychic vibrations that emanate from my active push emoticons.

I understand Graeme's assertion and am thinking about it, and no I would not agree that MX should be -basically rated at 320 ASA or more like 200 ASA practically, as many DPs told you.

Now be a nice man...okay?