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Author Topic: Phase One Trichromatic In Depth Article with Raw Files  (Read 10402 times)

Doug Peterson

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #40 on: October 23, 2017, 04:25:02 PM »

For those interested in discussing this article in person, both I and the Head of Phase One R+D will be at the DT / Phsea One Booth at Photo Plus this Friday.
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Doug Peterson

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #41 on: October 23, 2017, 04:31:44 PM »

Looking at the comparison "slider" images on the DT website, the difference is so small I just don't get it.  Personally I don't care that much about "accurate" color since I tweak them anyway in post.

Now here we have the implication your old back is no good so you need to upgrade. Not a chance.

DougDolde, could you please point me toward the passage in the article that you feel implies this? I'd like to modify any such passages as it was certainly not my intention to imply that.

For example:

"...this article will not answer whether you should purchase a Trichromatic. As a company DT doesn’t feel it’s our job to 'sell' – but rather that it’s our job to provide the tools, information, and testing opportunities that our clients need to evaluate whether, what, and when to buy."

"I think it’s suitable to say the native color response of the IQ3 100MP Trichromatic is 'Better Than the Best Ever.' But by no stretch of the imagination does that mean the previous 'best ever' was less than totally awesome. "

"Will that twinge be enough to justify the cost? As we said at the top, that’s not our call to make – it’s yours. Our job is to help you understand the decision you’re making as fully as possible. The color on the Trichromatic is improved over any camera we’ve ever used; in most cases the difference is subtle; in some cases of problematic subject matter the difference is quite large. The color on the traditional-CFA IQ3 100MP was and continues to be very good."

For what it's worth, the word "subtle" appears 8 times in our article.

All that said, "I don't care that much about color since I tweak them anyway in post" misses the point that in some cases the improved color discrimination will facilitate exactly that kind of post processing.
« Last Edit: October 23, 2017, 04:42:50 PM by Doug Peterson »
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Doug Peterson

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #42 on: October 23, 2017, 04:47:25 PM »

Whether those "tweaks" were significant or not depends on your disposition and what's important to you. And this is where I give Doug a break. DT, CI, Dodd, and all the other dealers I've had the pleasure doing business with say the same thing: Try it before you buy it. If you prefer the results, then buy if you want. If you do not prefer the results, or do not think the results are worth the price, don't buy it. ... as if P1 and its dealer network are advertising sugar-soaked cereal to unsuspecting 6 year-olds on TV. That is not the context of how this stuff is sold.

+1

The goal of the article is to help point out the goal of the product, and where you might observe differences.

Whether those goals are achieved, whether the differences are an improvement worth the cost involved are decisions for the client. We spend a lot of time and money internally making sure clients have the opportunity to do whatever additional testing, research, and consideration they need.
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Doug Peterson

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #43 on: October 23, 2017, 04:57:21 PM »

I believe that the Tri might have a very slight advantage in color reproduction (Doug's samples show this better than Phase' samples on their website) compared to the normal IQ3100 but still seams mainly a marketing hype to me.
I consider to attend a Trip demo this week in Munich, so let's see what I can report from there.
(I hope Phase sends also an engineer/physicist not only marketing people to be able to provide some profound information.)

I hope you're able to go to that demo. I don't keep track of the European events, but generally if someone from Phase One attends it is someone who is in R+D or product management; they rarely send someone out from the marketing team other than to observe. I've always found Phase One does an incredible job of making sure it's R+D people spend time out with real customers. Lau, Head of R+D, for example, will be at our DT / Phase One booth at PPE and our PPE Kickoff Party at Root Studios.

If you can't make it to the Munich event, I'm sure your local dealer can arrange for you to do your own testing at another time.
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DougDolde

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #44 on: October 23, 2017, 06:28:56 PM »

DougDolde, could you please point me toward the passage in the article that you feel implies this? I'd like to modify any such passages as it was certainly not my intention to imply that.

For example:

"...this article will not answer whether you should purchase a Trichromatic. As a company DT doesn’t feel it’s our job to 'sell' – but rather that it’s our job to provide the tools, information, and testing opportunities that our clients need to evaluate whether, what, and when to buy."

"I think it’s suitable to say the native color response of the IQ3 100MP Trichromatic is 'Better Than the Best Ever.' But by no stretch of the imagination does that mean the previous 'best ever' was less than totally awesome. "

"Will that twinge be enough to justify the cost? As we said at the top, that’s not our call to make – it’s yours. Our job is to help you understand the decision you’re making as fully as possible. The color on the Trichromatic is improved over any camera we’ve ever used; in most cases the difference is subtle; in some cases of problematic subject matter the difference is quite large. The color on the traditional-CFA IQ3 100MP was and continues to be very good."

For what it's worth, the word "subtle" appears 8 times in our article.

All that said, "I don't care that much about color since I tweak them anyway in post" misses the point that in some cases the improved color discrimination will facilitate exactly that kind of post processing.

Doesn't matter I can't afford a new back my IQ180 is just fine .
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Doug Peterson

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #45 on: October 23, 2017, 06:33:53 PM »

...my IQ180 is just fine .

Glad to hear you're enjoying your Phase One!  :D
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Garry Sarre

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #46 on: October 23, 2017, 07:02:11 PM »

Doesn't matter I can't afford a new back my IQ180 is just fine .

Doug Dolde, You make this comment

'Now here we have the implication your old back is no good so you need to upgrade. Not a chance.'

Doug Peterson gives you response, that would have taken 30 minutes out of his day, asking where that was implied; showing you examples where he had clearly stated that the previous backs were already great; asked you where he may have implied that they weren't so that he could edit that mis-understanding.

Perhaps an acknowledgement along the lines of....

'Yep, you're right, there was no such implication. Sorry about that. Thanks for taking the time to set that straight.'

A general comment for this forum, good manners are free.

As difficult as it may be when a bunch of geniuses get together, many members being experts in their respective fields, showing less arrogance, more humility and certainly, less of a chip-on-the-shoulder attitude would improve the acuity of discussion.


« Last Edit: October 23, 2017, 07:37:48 PM by Garry Sarre »
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ErikKaffehr

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #47 on: October 23, 2017, 07:26:54 PM »

Well,

Doug Peterson also makes the point that the IQ3100MP is perfectly good for Cultural Heritage reproductive work, and he doubts that the Thrichromatic would have a great advantage. But, they work with controlled light.

Doug Peterson also indicates that there may be specific colours like cobalt blue that are problematic. Cobalt blue is special that it has high reflectance in blue up to 540 nm and than virtually none up to 650 nm. After 650 it has high IR reflectance.

Unfiltered sensors have high sensivity in IR so IR would cause issue reproducing Cobalt Blue if Infrared was not filtered correctly.

All this is good information.

Best regards
Erik



Doug Dolde, You make this comment

'Now here we have the implication your old back is no good so you need to upgrade. Not a chance.'

Doug Peterson gives you response, that would have taken 30 minutes out of his day, asking where that was implied; showing you examples where he had clearly stated that the previous backs were already great; asked you where he may have implied that they weren't so that he could change any suggestion that they weren't.

Out of respect, I would have thought that your answer would have been.

'Yep, you're right, there was no such implication. Sorry about that. Thanks for taking the time to set that straight.'

Commenting generally of the genius forum.. good manners are free. Less arrogance, more humility and certainly, less of a chip-on-the-shoulder attitude would improve the acuity of discussion on the forum in general.
« Last Edit: October 23, 2017, 09:03:03 PM by ErikKaffehr »
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Manoli

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #48 on: October 23, 2017, 08:22:39 PM »

A general comment for this forum, good manners are free.

As difficult as it may be when a bunch of geniuses get together, many members being experts in their respective fields, showing less arrogance, more humility and certainly, less of a chip-on-the-shoulder attitude would improve the acuity of discussion.

ROTFL, 
Coming from the person who called one of the true ‘gentlemen’ of this forum ‘an insulting dick’ ...
patronising snd humbug, all rolled into one.

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eronald

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #49 on: October 24, 2017, 12:02:58 AM »

ROTFL, 
Coming from the person who called one of the true ‘gentlemen’ of this forum ‘an insulting dick’ ...
patronising snd humbug, all rolled into one.

Manoli

Yes, this discussion seems to be separating the mere humans from the Vulkans very nicely. Vulkans have this polite way of requesting factual evidence which seems to so terribly irritate humans.

Although I am fairly full of myself, one of the interesting things I learnt during my time as a participant in the ICC was that no one person knows everything about photographic color, it is a collectively held body of knowledge and practice which brings together scientists, engineers, practitioners and even artists, and any attempt to promote one competence over the others is doomed to frustrate.

Edmund
« Last Edit: October 24, 2017, 12:34:01 AM by eronald »
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torger

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #50 on: October 24, 2017, 01:54:42 AM »

Hmmm. You lost me right about there. The whole concept of a bayer sensor, at least a sensor with non-trivial overlap, having "saturation" is not, IMHO, very useful. They really don't (a) in any way that it's useful for a human to think about or (b) in any way that makes sense in a mathematical form.

Let me examplify. A saturated red color: with lots of overlap the raw value may become 100% R 40%G and 20% B. With little overlap 100% R 10% G and 0% B.
If you without any camera profile just display that on screen (white balanced to not make it look green) the color from the sensor with less overlap is more saturated.
« Last Edit: October 24, 2017, 02:25:42 AM by torger »
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torger

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #51 on: October 24, 2017, 01:56:26 AM »

Agree with that, unless the sensors are Luther-Ives compliant (and then the saturation would be perfect by definition). I took the remark to discuss colors after multiplication by the compromise matrix, however.

I meant before matrix multiplication, but after white balancing if you like. Basically what you get if you "export image for profiling" from Capture One.
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torger

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #52 on: October 24, 2017, 02:15:57 AM »

This is news to me. In the work that Jack Hogan and I have done so far on the relationship of overlap and SMI, it appears that SMI suffers when there is too much and when there is too little overlap. We have not -- so far -- investigated the direction of the errors.

Are you suggesting that in the computation of the optimum compromise matrix that reducing overlap biases the errors wrt the reference values for the training set in the direction of increased chroma?

It should be possible to test that, but before I do so, I want to verify if that's what you are claiming.

The experience I'm basing the discussion on is my work with camera profiling. Sensors that are low in noise and have a good amount of overlap are generally easier to control in the direction you want, compared to those that have little overlap, especially combined with high noise. The reason being that in the first case you always have good amount of clean signal in all three channels also in highly saturated colors which you can recombine in the way you want, and in the second case you have little to play with in one or two channels when colors are saturated. The problem with overlap however is that the signal difference between different colors are smaller, so it relies on that it is balanced with the noise level. With little overlap you instead have larger signal difference between similar colors, which is good, but the drawback is that the overall color response is more difficult to control.

This is a very broad description though, sure there is a balance somewhere. There is things like "too much overlap" and "too high sensitivity in the wrong places" that makes it difficult to make camera profiles, especially too strong blue sensitivity is something I have seen a lot of. I've only worked with older sensors when it comes to having less overlap, having a low noise sensor with less overlap is indeed interesting. One can really only know how this camera behaves until trying it out. What I reacted to was the marketing material showing this quite little overlap and claiming that as an outright advantage, when my experience from profiling suggests that it can be quite problematic.

Note that typical matrix-related testing of color response only test moderately saturated colors. It's generally in higher saturations you start seeing problems, when it's more clear that the camera "wants" the color to be in a certain way. Try to pull it in your desired direction and all related must follow (all the way into lower normal saturation) or you must make a strongly non-linear profile with potential gradient issues, or you simply ignore how the high saturation colors end up and just optimize for the normal range. Therefore I don't think that SMI is very telling, any modern camera has a good SMI value regardless if it has a response that is difficult or easy to control end-to-end.

I haven't really come up with a good way to actually test for "camera profile friendliness" other than actually making camera profiles. I guess a matrix test which include matching of high saturation colors, that is not just a MacBeth CC24, but something like X-Rite's semi-glossy CCSG, could yield some interesting results. The key parameter I would look for I think would be if it linearly can represent the same hue from low to high saturation, lightness and saturation matching is less important.

If a sensor is difficult to work with, what you end up with is one of the following compromises: 1) good normal color, bad behavior in the extremes, 2) robust behavior in the extremes less good normal colors, 3) robust behavior in the extremes, good normal colors, poor transition between the two, 4) robust behavior throughout the range with a look adapted to fit camera behavior end to end. The last does not need to be a compromise, it just means that hues are not necessarily made to be realistic but to match what the camera wants them to be. For example making blues more cyan, reds more yellow which are popular elements in a look. As Phase One has designed both CFA and profile my guess is that have optimized it for their specific look rather than for being flexible to adapt any desired look.
« Last Edit: October 24, 2017, 03:40:21 AM by torger »
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Gigi

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #53 on: October 24, 2017, 05:37:48 AM »

One dares not enter this discussion of color theory, sensors and advanced electronics lightly, but from a distance it seems Doug has responded politely to some rather caustic comments. Leaving the facts to others more knowledgeable, it seems the dealer here (DT) is simply positioning information and explanations and not over-asserting benefits. That is worthwhile. Thanks for the grace.
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sandymc

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #54 on: October 24, 2017, 06:16:37 AM »

Let me examplify. A saturated red color: with lots of overlap the raw value may become 100% R 40%G and 20% B. With little overlap 100% R 10% G and 0% B.
If you without any camera profile just display that on screen (white balanced to not make it look green) the color from the sensor with less overlap is more saturated.

The problem is, you can't really display an an image without a camera profile. What you describe there is actually a profile with a unity diagonal, and no tables, but it's still a profile.

Sandy
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torger

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #55 on: October 24, 2017, 06:38:08 AM »

The problem is, you can't really display an an image without a camera profile. What you describe there is actually a profile with a unity diagonal, and no tables, but it's still a profile.

Yep, true. I should have been more clear. What I mean with saturation in this context from a mathematical perspective is simply a larger span from the largest to the smallest value in the raw channels for a specific color. Advantage: larger difference between similar colors, disadvantage: low signal in the lower value channels making it harder to pull the color in a different direction than the camera "wants". It's not entirely clear cut though. It would be interesting to have the actual sensitivity functions from both the new and the old to play with and see how they compare in different scenarios.

Phase One is not exactly new in this game, they know what they are doing for sure. If they have optimized the camera to present a specific look, making tests to see how well it can serve as a reproduction device (which basically all objective color testing is about) may make it look bad although it serves the designed look very well. It's not entirely clear to me what the design goal has been though, I haven't read all material out there though maybe the information is there somewhere.

Personally I prefer cameras that are "neutral" and work well both as reproduction devices and subjective color profiles, not only for the look decided by the manufacturer. I can accept a tad bit of more noise to achieve this goal. My suspicion is that this new camera is due to the less overlapping filters less neutral and more optimized for Phase One's look, and thus will be great for those that love that look, but a step backwards for others. I don't know if this really is the case or not though as there is so many factors involved, and although less overlapping than the old they can still have quite much overlap left.

Related, this presentation contains some nice examples of what happens if the CFA has certain shapes:
http://www.slideserve.com/nigel/theoretical-and-practical-limits-to-wide-color-gamut-imaging-in-objects-reproducers-and-cameras
« Last Edit: October 24, 2017, 07:02:53 AM by torger »
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sandymc

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #56 on: October 24, 2017, 07:34:52 AM »

Related, this presentation contains some nice examples of what happens if the CFA has certain shapes:
http://www.slideserve.com/nigel/theoretical-and-practical-limits-to-wide-color-gamut-imaging-in-objects-reproducers-and-cameras

Thanks, that is interesting - especially as regards slide film!

Sandy
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eronald

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #57 on: October 24, 2017, 06:08:54 PM »

For those interested in discussing this article in person, both I and the Head of Phase One R+D will be at the DT / Phsea One Booth at Photo Plus this Friday.

Doug, the audience in this forum is well known and require hard evidence. You might get proactive and publish the *real* CFA curves rather than lose control of the spin when someone else does it . As these curves can be measured, there is no way you can argue they are a trade secret. I am sure there are plenty of nasty things one can find to say about anybody here, but if you *choose* to post about color technology in a forum where many participants are engineers, software authors or even senile PhDs  like me you can expect scepticism in the absence of hard data.

Edmund
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ErikKaffehr

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #58 on: October 24, 2017, 08:42:33 PM »

Hi Edmund,

I agree with what you say. It is probably right as you say, the CFA data can be measured easily. That is if you have access to a back. It does not take fancy gear to do. Jack Hogan has measured the CFA response of his Nikon D90 using a 39$ spectrometer, and came up with this:



He used sunlight as light source. The spectrogram calibrates it self as it contains atomic absorbance lines from gases contained in the Sun's athmosphere.

My issue is not what Doug's article does not show, it is that his article states rather than implies that traditional CFA:s are like this:



But all spectral data I have seen was like the one posted by Jack Hogan. That also applies to data published by Kodak and DALSA for the backs used by Phase One in previous CCD based designs. The exception would be digital camera sensor where the IR-filter was removed. This is a modfication that is made for IR.

Phase One could add a tremendous amount of credibility to their info on "colour science" would they show the curves for the the IQ3100MP and the Thrichromatic side by side and explain the differences instead of using "artist vision" of the data.

You are right, some of the guys posting are engineer, some are developing camera profiling tools and some are deloping raw conversion software. Personally, I can not take credit for anything like that. But even amateurs can have some experience with real world data.

BTW, the presentation Anders Torger has linked to is quite interesting:
http://www.slideserve.com/nigel/theoretical-and-practical-limits-to-wide-color-gamut-imaging-in-objects-reproducers-and-cameras

Best regards
Erik

Doug, the audience in this forum is well known and require hard evidence. You might get proactive and publish the *real* CFA curves rather than lose control of the spin when someone else does it . As these curves can be measured, there is no way you can argue they are a trade secret. I am sure there are plenty of nasty things one can find to say about anybody here, but if you *choose* to post about color technology in a forum where many participants are engineers, software authors or even senile PhDs  like me you can expect scepticism in the absence of hard data.

Edmund
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eronald

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #59 on: October 24, 2017, 09:25:49 PM »

Hi Edmund,

I agree with what you say. It is probably right as you say, the CFA data can be measured easily. That is if you have access to a back. It does not take fancy gear to do. Jack Hogan has measured the CFA response of his Nikon D90 using a 39$ spectrometer, and came up with this:
-------
You are right, some of the guys posting are engineer, some are developing camera profiling tools and some are deloping raw conversion software. Personally, I can not take credit for anything like that. But even amateurs can have some experience with real world data.

Erik

Hi Erik,

In my book, you are a Vulcan and a gentleman ;)

Can you link the *post* where Jack details his method? I think Iliah once told me to just get a monochromator from ebay, and of course university labs own all the stuff required.

Edmund
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