Phase One Trichromatic In Depth Article with Raw Files

[ErikKaffehr]

Hi Edmund,

Thanks for the kind words! But even Vulcans can erupt, now and than.

Here is the link: http://www.strollswithmydog.com/bayer-cfa-spectral-power-distribution/

Best regards
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

[narikin]

I borrowed a Trichromatic for the weekend a little while back, and was underwhelmed, I have to say.
As Doug hints, if you own an IQ100 already, which has really good color, you are going to have to pixel peep furiously to notice any difference.

I note that Doug says the IQ100 has a base Iso of 50, whereas they said at the launch it was 100. They promoted it as that, to mark it as a step up from the old 80mp IQ CCD sensor's low 35iso base sensitivity. Now they want to say the opposite!

However they did put this line out:

"The Phase One IQ3 50mp carried a base ISO of 100. The Phase One IQ3 100mp has a lower minimum ISO of 50"

note they don't call it 'Base ISO', but 'lower minimum' that implies that 50asa is a pull stop, not a true base ISO.

This means the speed/ sensitivity loss is not 2/3 stop, but 1 2/3 stops. A big difference. I work handheld on location, and 200asa is my default, it just works great on the IQ100, but is not nearly as good on the Trichromatic - too noisy. This is me, ymmv, a great, clean 200asa may not matter to you, but I'm sticking with my IQ100, as it is really important to me.

[hubell]

You will initially save money by not upgrading now from the IQ100 to the Trichromatic 100MP, but then when you go to trade in the IQ100 against the IQ150 Trichromatic, you will take a hit. By issuing the Trichromatic Technology now in a new back, Phase will be nicely set up for the limiting the trade in value of the IQ100s against the IQ150 Trichromatic. I am not suggesting anything devious, just pointing out the economic reality.

[Christopher]

I wouldn’t say that. On my experience the worst trade in value is a crosstrade you can say what you want but it’s just that. Iq3100 to the trichromatic. I expect the upgrade from the IQ3100 to the IQ4150 much more attractive.

We will see how it actually is at that point.

Sorry for the off topic post.


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[bjanes]

Hi,

Doug's posting is not a scientific article but it does contain some alternate facts.

Doug shows a spectral plot of traditional CFA filters:


But, traditional filters look like this:


Or this:


Or this:


So Doug illustrates traditional CFA designs with fake info. There is a sensor that has some characteristics similar to the traditional CFA illustration in Doug's presentation and that is the human vision, corresponding to curve A, below:


The reason such curves are not used in digital cameras is that it would cause excessive levels of noise.

Regarding UV-filtering and IR filtering, that is really a job for the cover glass, that has an IR-filter. Optical glass doesn't transmit much in UV anyway. If UV/IR is an issue, it is not about a new design, it is about Phase One designing an underperforming cover glass on the older models.

The colour differences Doug demonstrate are well within the capabilities of properly designed camera profiles. The effects shown can possibly achieved just buying a proper test target and use Lumariver's Profile Designer.

So, my impression is that it is a marketing hyperbole. The curves that Doug shows are patently fake. If the article starts with fake facts, why would be believe the rest?

To Dougs's defense, I would assume that he just uses info he got from Phase One, but I don't think he should have use it as to much of the info is fake and it should be obvious to anyone doing colour stuff.

Best regards
Erik

On glancing at Doug's article, I immediately saw that his spectral response of a "typical CFA" was nothing like the spectral response of CFAs of actual dSLRs that I had seen in the literature. I commend Erik for pointing out the unscientific nature of the article with fake data. LuLa apparently lacks technical editors with a scientific background and entrusted the validity of the article to a salesman. 

Spectral responses of sensors are typically done with a monochromator and these are available mainly in specialized laboratories in industry and academia. Here is a link (shown in the linked CFA response image) to a German thesis using interference filters rather than a monochromator. The thesis has spectral responses to various cameras in the appendix. Shown here is one for the Nikon D700. It is nothing like Doug's typical CFA.

Bernard  Delley has recently published a comparison of the spectral responses of Nikon sensors from the D800 to the D500. Not peer reviewed, but it appears well done and he confirms work previously done by Marianne Oelund who is a highly respected contributor to these forums. These curves are nothing like Doug's "typical" curves.

LuLa should retract or heavily revise Doug's article and employ a qualified technical editor.

Regards,

Bill

[eronald]

On glancing at Doug's article, I immediately saw that his spectral response of a "typical CFA" was nothing like the spectral response of CFAs of actual dSLRs that I had seen in the literature.

---
Bill

Bill
 I see that yet another Vulcan lover of fact and logic just got here
 I am not very qualified in the theory of color science as I only took Professor Hunt's short course. This lack of education may be the reason why the text in Doug's article seems a bit hard to grok.
 HoweverI like the photographs
. If the article were reduced to the photos it would be both a good article and a good sales tool.
 Maybe one line more: "We have spent xx years improving the color in our backs, and this is what we have to show you"

Edmund

[ErikKaffehr]

Hi Edmund,

I just ordered The Reproduction of Colour by R. W. G. Hunt on your inspiration.

You may find this posting of some interest: https://www.getdpi.com/forum/medium-format-systems-and-digital-backs/62676-phase-one-trichromatic-depth-article-raw-files.html#post742819

Best regards
Erik

Bill
 I see that yet another Vulcan lover of fact and logic just got here
 I am not very qualified in the theory of color science as I only took Professor Hunt's short course. This lack of education may be the reason why the text in Doug's article seems a bit hard to grok.
 HoweverI like the photographs
. If the article were reduced to the photos it would be both a good article and a good sales tool.
 Maybe one line more: "We have spent xx years improving the color in our backs, and this is what we have to show you"

Edmund

[32BT]

Hi Edmund,

I just ordered The Reproduction of Colour by R. W. G. Hunt on your inspiration.

You may find this posting of some interest: https://www.getdpi.com/forum/medium-format-systems-and-digital-backs/62676-phase-one-trichromatic-depth-article-raw-files.html#post742819

Best regards
Erik

Interesting comparison. Though i'd like to point out that ir and uv oddities that may occur with normal daylight spectrum will likely be less of an issue with proper artificial light. 

The difference in red rendition is notable. Did you try to increase contrast in the first image to see how close it gets to the bottomleft? Or visa versa, decreasing in bottomleft to match topleft?

[eronald]

Interesting comparison. Though i'd like to point out that ir and uv oddities that may occur with normal daylight spectrum will likely be less of an issue with proper artificial light. 

The difference in red rendition is notable. Did you try to increase contrast in the first image to see how close it gets to the bottomleft? Or visa versa, decreasing in bottomleft to match topleft?

In the days when digital photography was gaining acceptance, it was usual to shoot with a HOT filter, I remember the name from descriptions. Maybe a filter in front of the lens is a good idea, generally, of course it would be necessary to reprofile, not least because Phase profiles are a bit tweaked to deal with IR issues, I seem to recall.

I think that when shooting paintings one can find pigment combinations that break *any* specific commercial Bayer filter.

Edmund


 

[Doug Peterson]

I quote myself from the first part of the article:

What This Article Will and Will Not Contain
If you came to this two-part article hoping for a PhD dissertation on color science you’ll be disappointed. I do not hold a PhD in color science, nor do many of our clients. If you’re hoping this article will contain precise 10nm-sliced spectral transmission curves generated by a monochromator, along with associated data tables, then you’ll be disappointed [...] Personally, I won’t shed tears over either of these omissions; in my experience neither PhD dissertation nor highly detailed Spectral Transmission Data is of all that much value to a photographer deciding which equipment is the best fit to their needs and budget.

In short, if your interests lean more toward the academic study of color science than toward the daily practice of photography then this article is not for you.

The charts are very clearly described in the article as "crudely drawn" with "exaggerated differences to make them easier to consume" which "should not be taken literally" – coming to this thread and decrying their lack of scientific accuracy is missing the point to say the least. That said, they are not "fake" as the direct comparisons I've posted shows.

If anyone would like to write an academically-oriented article on the Trichromatic CFA we are very glad to help! We will gladly provide a back and work bench at our LA or NYC office for your testing at no cost, or arrange a reasonable way for you to evaluate it elsewhere in the US. We will gladly connect you to the Phase One R+D team to ask questions. I'm even glad to connect you to a few of the PHDs in color science that I communicate with on a regular basis should you wish to have your article peer reviewed and published in an academic journal. If you'll allow us, we (DT) will gladly publish your results on our blog, and though I can't speak on their behalf I suspect strongly Luminous Landscape would be glad to publish on their page (and for sure, you are welcome to post to the forum). I'm not being facetious or sarcastic; please feel free to contact me to start that process.

Until then, please consider the intended audience of our article and the difficult task of trying to provide some entry-level education on a topic as complex and dry as color science to a group as diverse as "photographers".

[eronald]

Hi Edmund,

I just ordered The Reproduction of Colour by R. W. G. Hunt on your inspiration.
Best regards
Erik

Erik,

This may be of interest to you
 http://eu.wiley.com/WileyCDA/WileyTitle/productCd-0470665696.html
 https://fr.mathworks.com/matlabcentral/fileexchange/40640-computational-colour-science-using-matlab-2e?focused=3779527&tab=function

I never (carefully) read this book. After taking the Hunt course, as an exercise, I coded up a camera profiler for my P45+, and got quite decent profiles, better than the Phase One canned ones in real use; Matlab is useful in this context because  handles all the profile-specific file IO for you, you just need to establish the matrix. At this level of work, you do need a ColorMunki or equivalent Spectro to measure the targets.

In the end any attempt to use a Bayer sensor is doomed to have issues and in my opinion  it is important to realise that and take a creative view of color. Frankly I find painting much more fun these days than photography, partly because *I* am the only one to blame for bad color.

Edmund

[eronald]

Doug,

 Let me try and be helpful here.

 A lot of money and work clearly went into a new CFA design, and the product is now on the market and Phase One are proud of it.

 I would expect this Phase One product to have very good color. Phase One have always been known for very good color. Professional photographers, institutions and enthusiasts buy Phase One for image quality, they don't buy Phase One cameras because they shoot 20 images a second.

 The reason you are getting criticised for your post has nothing to do with Phase quality, it's a PR issue: you don't understand the culture of the color community, which is full of "geeks" and outside your personal expertise.  The way color works is traditionally by full disclosure of behaviours, not production methods. Even Kodak and Fuji used to publish curves for their films.  The reason why color works by disclosure is that everybody from makeup manufacturer through flash maker, photographer to printer and framer needs to understand a bit about everybody else's problems. Putting something on the market that innovates, without explaining, almost always means you break someone else's workflow product - think lipstick or lights.

As everything can be tested, why not get out in front of these issues, publish the real test curves, or even better hire some known color geek to spend a week collecting the documentation and running tests and compile a standard summary. Add a couple of carefully lit target test-shots and software geeks will be able to test their own profiling engines, and avoid surprises. At classic Phase prices, $5K for a week's work is probably 12% of the price of a back ...surely that is an acceptable marketing cost?  Your expert doesn't need to be "independent", just respected, it's not about bias, it's about understanding the amount of information which is expected by the community.

I am astonished that someone as skilled as you at reading the market has even momentarily forgotten that camera marketing is all about putting your right foot forward, wearing a tuxedo in some places even if torn jeans are preferred in other venues. The fashion photography crowd expects a launch party, the geeks want color curves.

Edmund

I quote myself from the first part of the article:
In short, if your interests lean more toward the academic study of color science than toward the daily practice of photography then this article is not for you.

The charts are very clearly described in the article as "crudely drawn" with "exaggerated differences to make them easier to consume" which "should not be taken literally" – coming to this thread and decrying their lack of scientific accuracy is missing the point to say the least. To say they are "fake" when I've posted a direct comparison showing their key features in specific cameras is insulting. But that's okay; one doesn't write articles on the internet without expecting to be insulted by someone somewhere .

If anyone would like to write an academically-oriented article on the Trichromatic CFA we are very glad to help! We will gladly provide a back and work bench at our LA or NYC office for your testing at no cost, or arrange a reasonable way for you to evaluate it elsewhere in the US. We will gladly connect you to the Phase One R+D team to ask questions. I'm even glad to connect you to a few of the PHDs in color science that I communicate with on a regular basis should you wish to have your article peer reviewed and published in an academic journal. If you'll allow us, we (DT) will gladly publish your results on our blog, and though I can't speak on their behalf I suspect strongly Luminous Landscape would be glad to publish on their page (and for sure, you are welcome to post to the forum). I'm not being facetious or sarcastic; please feel free to contact me to start that process.

Until then, please consider the intended audience of our article and the difficult task of trying to provide some entry-level education on a topic as complex and dry as color science to a group as diverse as "photographers".

[Doug Peterson]

The reason you are getting criticised for your post has nothing to do with Phase quality, it's a PR issue: you don't understand the culture of the color community. [...] The fashion photography crowd expects a launch party, the geeks want color curves.

Our article was not for the "color community" (i.e. academics immersed in matrices, measurement, metamerism, and minutia). 

Our article was for photographers – our clients. So far as I can tell it was very well received by that community.

It's really understandable if color PHDs found the article lacking in academic details. I literally stated in the introduction to the article that they would "disappointed".

It's a bit like I hosted a Wine Tasting Night and noted on the invite "Before the tasting, a brief introduction of wine will be given. Wine making is a rich and complex topic. If you're a professional sommelier you will find our explanations oversimplified or even technically inaccurate." and then a few soms attended and complained that I didn't provide detailed terra acidity analysis studies. We're glad to host those soms at the winery to do their own soil tests; the Wine Tasting Night just wasn't the proper time and place for it.

[eronald]

Doug,

 If you tell *us* that the Phase Sony chip is "better" than the Sony sensor inside a $7K Pentax  then you'd better show some better evidence that it is indeed better because $$$$ is the sort of numbers many here understand without a PhD, and to say the least there has been some skepticism. And it does seem to me that this forum is on the same site as your 2-part effort

 BTW the question of whether a black dress or a black pair of sneakers  will photograph as black or magenta is really crucial to many photographers but there are only two ways of knowing, one is by taking the picture and the other by looking at those curves which you make fun off. Telling people "here is the curve, this shows what it does" makes sense. In the same way, printers run expensive spectros not because they have PhDs but because color is about contracts and money.

Edmund

Our article was not for the "color community" (i.e. academics immersed in matrices, measurement, metamerism, and minutia). 

Our article was for photographers – our clients. So far as I can tell it was very well received by that community.

I'm really okay if color PHDs found the article lacking in academic details. I literally said in the introduction to the article that they would "disappointed".

[ErikKaffehr]

Hi,

It does not take a PHD in colour science to see the article misstates facts. It is quite enough to have seen some spectral plots from traditional cameras.

It is in no way clear that non overlapping filters are advantageous regarding color rendition, on the contrary overlap is needed to render colours correctly. This thread covers a lot of ground: https://www.dpreview.com/forums/post/60278621

Best regards
Erik

Our article was not for the "color community" (i.e. academics immersed in matrices, measurement, metamerism, and minutia). 

Our article was for photographers – our clients. So far as I can tell it was very well received by that community.

It's really understandable if color PHDs found the article lacking in academic details. I literally stated in the introduction to the article that they would "disappointed".

It's a bit like I hosted a Wine Tasting Night and noted on the invite "Before the tasting, a brief introduction of wine will be given. Wine making is a rich and complex topic. If you're a professional sommelier you will find our explanations oversimplified or even technically inaccurate." and then a few soms attended and complained that I didn't provide detailed terra acidity analysis studies. We're glad to host those soms at the winery to do their own soil tests; the Wine Tasting Night just wasn't the proper time and place for it.

[Jack Hogan]

I just ordered The Reproduction of Colour by R. W. G. Hunt on your inspiration.

Hi Erik,

Hunt's model of color vision is very clearly explained in his book 'Measuring Color'.  I find it much more relevant to photography and prefer it to 'The Reproduction', which I also own.

Jack

[ErikKaffehr]

Hi Jack,

Thanks for the info, it seems I need to cancel one order and make another one!

Best regards
Erik

Hi Erik,

Hunt's model of color vision is very clearly explained in his book 'Measuring Color'.  I find it much more relevant to photography and prefer it to 'The Reproduction', which I also own.

Jack

[Wayne Fox]

While I might agree that Doug’s plots over emphasized the red contamination, the spectral plots of many of the cameras posted indicate to me there is plenty of red contamination getting all the way into the blue and green sensels that perhaps cleaning this up and creating more consistent crossover would offer some advantage.

As to whether it can be corrected with custom profiles, perhaps it might be improved but perhaps most photographers really don’t want to get into the technical aspect of creating their own profiles, If the camera and CFA’s can be engineered to provide a better solution, why not?  While the current price point doesn’t make sense for most, like anything new, if it’s good and helpful, it will trickle into other products over time most likely with far less impact on price.

In reviewing the article, I actually wonder if his two original graphs are labeled backwards, because he does state one is based on the eye, other on a sensor, but the way they are shown the graph that is typical of one used for the eye is labeled as a sensor and vice versa.

[ErikKaffehr]

Hi Opgr,

Thanks for making the point on light, I don't think Doug specifies the illumination. I think electronic flash has significant IR.

Regarding rendition differences, I have processed one of the P45+ images with Capture One the other with Lightroom CC Classic. The C1 image has more snap.

I reprocessed the image in LR CC Classic, but using an emulation of Capture One's film-curve instead of ACR tone-curve in my DCP profile. In addition I increased "Vibrance" from 0 to 10 and also "clarity" from 0 to 10.

Here are the results:

Left Capture One, defaults except exposure. Center Lightroom CC with Capture One Film Curve and +10 in vibrance and +10 in clarity. Right Lightroom CC with ACR-tone curve, 0 vibrance and 0  clarity.

What is your take?

Best regards
Erik

Interesting comparison. Though i'd like to point out that ir and uv oddities that may occur with normal daylight spectrum will likely be less of an issue with proper artificial light. 

The difference in red rendition is notable. Did you try to increase contrast in the first image to see how close it gets to the bottomleft? Or visa versa, decreasing in bottomleft to match topleft?

[BobShaw]

Please don't change the name of the subject

It gives the illusion that something worth reading has been said.