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Author Topic: Phase One Trichromatic In Depth Article with Raw Files  (Read 34214 times)

E.J. Peiker

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #100 on: December 29, 2017, 02:22:27 pm »

A new very complimentary article on the Trichromatic back:
https://fstoppers.com/originals/phase-one-iq3-100mp-trichromatic-colors-compared-209065
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Jack Hogan

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #101 on: January 01, 2018, 12:10:12 pm »

Hmm, I don't think he can draw the conclusions he is drawing based on that test: one image is more saturated than the other, contrast seems to be different and he says one has a color cast = at least one 'incorrect' profile.  As a result I am also not convinced about the color noise and chromatic aberration claims: could be a lens profile issue.  And doesn't the IQ3-100 standard back normally take a hot plate?

In the end he may well be right but I don't think the procedure he used can lead to such conclusions.
Jack
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ErikKaffehr

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #102 on: January 01, 2018, 12:50:33 pm »

Hi Jack,

My guess is that part of the difference that can be observed may depend on different cut off regarding IR or UV, that could effect axial chroma and also explain some of the yellow contamination of vegetable greens that some observers object to with Phase backs.


Top left, Lightroom with Lumariver profile. Top Right Capture One
Bottom Left, IQ3100 with Lumariver profile, Bottom Right Capture One.

Best regards
Erik

Hmm, I don't think he can draw the conclusions he is drawing based on that test: one image is more saturated than the other, contrast seems to be different and he says one has a color cast = at least one 'incorrect' profile.  As a result I am also not convinced about the color noise and chromatic aberration claims: could be a lens profile issue.  And doesn't the IQ3-100 standard back normally take a hot plate?

In the end he may well be right but I don't think the procedure he used can lead to such conclusions.
Jack
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dchew

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #103 on: January 01, 2018, 05:50:06 pm »

The one thing he says in that test is, "White balance is exactly the same for both images...". I assume that means the Temperature and Tint sliders were identical. I suppose that is useful for highlighting how a camera responds to lighting, but I don't know how practical it is. I think it is more useful to white balance both on the color checker and evaluate colors with a balanced file.

I also do not understand his second image about chromatic aberrations. In the first image, that scale looks much more "magenta" in the Trichromatic image. Either he mixed those up or it is a different image. I didn't see that when I tested them, but then again I wasn't looking for it.

Erik, how did you get a Lumariver profile for the backs? Did you create them from that file? If you did, great idea! In other words, why didn't I think of that? Curious because the apple looks exactly the same as it did with mine on the 3100. Reds look darker on the Lumariver / Trichromatic file too. Must be Anders' personal spin on the twists.
:)

Dave
« Last Edit: January 05, 2018, 08:41:37 am by dchew »
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ErikKaffehr

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #104 on: January 01, 2018, 07:46:04 pm »

Hi Dave,

Yes, I created the Lumariver profile from your image.

Best regards
Erik

The one thing he says in that test is, "White balance is exactly the same for both images...". I assume that means the Temperature and Tint sliders were identical. I suppose that is useful for highlighting how a camera responds to lighting, but I don't know how practical it is. I think it is more useful to white balance both on the color checker and evaluate colors with a balanced file.

I also do not understand his second image about chromatic aberrations. In the first image, that scale looks much more "magenta" in the Trichromatic image. Either he mixed those up or it is a different image. I didn't see that when I tested them, but then again I wasn't looking for it.

Erik, how did you get a Lumariver profile for the backs? Did you create them from that file? If you did, great idea! In other words, why didn't I think of that? Curious because the apple looks exactly the same as it did with mine on the 3100. Reds look darker on the Lumariver / Trichromatic file too. Must be Anders' personal spin on the twists.
:)

Dave

Dave
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Jack Hogan

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #105 on: January 02, 2018, 04:07:30 am »

Hi Jack,

My guess is that part of the difference that can be observed may depend on different cut off regarding IR or UV, that could effect axial chroma and also explain some of the yellow contamination of vegetable greens that some observers object to with Phase backs.

Could be Erik.  Doesn't the standard back IQ3100 have a hot plate (IR/UV filter)?


Top left, Lightroom with Lumariver profile. Top Right Capture One
Bottom Left, IQ3100 with Lumariver profile, Bottom Right Capture One.

One row is Trichromatic the other one is standard back?  Anders' profiles are obviously better.  Have you computed deltaE's?

Jack
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Doug Peterson

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #106 on: January 02, 2018, 10:10:37 am »

One row is Trichromatic the other one is standard back?  Anders' profiles are obviously better.  Have you computed deltaE's?

It is not terribly useful to measure the DeltaE of the target from which you made a profile. It's like telling someone that your father's name is "Edward" followed by quizzing them on their knowledge of your family by asking them the name of your father... of course they will get that right; if you teach to the test the test tells you about the teaching, but not about the underlying knowledge.

The proper thing is to create a target from one type of target and then measure the DeltaE on an entirely different make/model of target.

Discussed in more depth in our Color Guide.

Of course that's an entirely different discussion from whether DeltaE is the most useful metric when talking about real-world photography as opposed to art reproduction. My opinion is that looking at the image is more useful than taking scientific colormetric measurements of patches, but I acknowledge it's reasonable to disagree with that opinion.
« Last Edit: January 02, 2018, 10:16:55 am by Doug Peterson »
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Alexey.Danilchenko

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #107 on: January 02, 2018, 11:16:23 am »

It is not terribly useful to measure the DeltaE of the target from which you made a profile. It's like telling someone that your father's name is "Edward" followed by quizzing them on their knowledge of your family by asking them the name of your father... of course they will get that right; if you teach to the test the test tells you about the teaching, but not about the underlying knowledge.
It is not useful to use the same shot from which profile was made yes. The same target is perfectly useful - shot under different lighting for example to evaluate your profile behavior. It is even more useful if profile was build from spectral sensor measurements even for that very target - to evaluate the profile.
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dchew

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #108 on: January 02, 2018, 11:30:25 am »

BTW, raw files of those images Erik used are available here, along with others.
TCv3100 Hightail link
The last file is a legend in excel.

Dave
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ErikKaffehr

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #109 on: January 02, 2018, 12:01:54 pm »

Hi Jack,

I think there is some difference in tone curves between my profiles. I have not calculated delta E's, at least yet.

What I have thinking about was that Tim Parkin and Jow Cornish has expressed grave concern about yellow contamination of chlorophyll greens with the P45+. Measuring spectral reflections on leaves and flower blades I have found that they had pretty extreme reflection in near infrared that is absent in the color checker patches. That got me thinking about IR contamination.

Now, with the DALSA based backs Tim Parkin and Joe Cornish stated that the colour issues went away.

In some of my later shots with the P45+ I noted that I had a magenta/brownisch tone on my black backdrop. That has also been seen with the Leica M8, due to weak IR filtration.

Doug Peterson indicated that lime green was yellowish on the IQ3100 MP and essentially mentioned the near IR issue.

I did a test with three cameras I have, the P45+, Sony A900 and Sony A7rII and all were perfectly capable to reproduce lime greens under near D50 flash light. I know that because I replaced patches in my images with measured spectral data and the patches based on spectral data were simply not visible in Adobe RGB, indicating a pretty perfect match. The way I checked this was using L*a*b* and pasting in the 'a*' and 'b*' channels while keeping 'L*' intact.

The images by SonderCreative indicate a lot of out and focus green/magenta fringing on out of focus images. That is pretty much a strong indication of axial chroma. Lloyd Chambers has found that issue with the lenses for the Leica S, but he also found that the aberration would go away with either UV or IR cut off filters, I don't recall witch.

Anyway, the strong fringing in SonderCreative's images indicates that the lenses are not well corrected in the frequency range the IQ3100MP sensor detects. The lack of axial chroma in the images from the Thrichromatic strongly indicates that IR or UV filtering is different.

So, my conclusion from those imagesis that IR/UV cutoff on the Thrichromatic is probably stronger.

It was Doug's posting that led me look into "lime greens". I can not say anything else than that the three sensor I happen to have access to handled lime green perfectly well under near D50 electronic flash.

Best regards
Erik



Could be Erik.  Doesn't the standard back IQ3100 have a hot plate (IR/UV filter)?


One row is Trichromatic the other one is standard back?  Anders' profiles are obviously better.  Have you computed deltaE's?

Jack
« Last Edit: January 02, 2018, 12:30:37 pm by ErikKaffehr »
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Erik Kaffehr
 

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #110 on: January 02, 2018, 01:11:40 pm »

; if you teach to the test the test tells you about the teaching, but not about the underlying knowledge.

I believe that the analogy may be appropriate for lut-based profiles, but is specifically inappropriate for matrix profiles. It is exactly the "underlying knowledge" that can be depended on if the original target matches, especially if the colors of that target fall well within the possible space.

The "underlying knowledge" in this case meaning that the device has a linear response (not meaning "linearized" response). Of course, that linear response can be questioned, since the sensor likely doesn't respond linear at the far ends of the data which means ETTR best practices can also be questioned, but that is a different can of worms altogether.

Another can of worms however is the highlight priority curves required for stuffing the dr of captured data into a reasonable image. That is clearly going to affect the results of a diect match.
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ErikKaffehr

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #111 on: January 02, 2018, 02:23:24 pm »

Hi Dave,

Thanks for sharing! I realize that I should give credits for the images! Somewhat belatedly, thank you very much!

Best regards
Erik


BTW, raw files of those images Erik used are available here, along with others.
TCv3100 Hightail link
The last file is a legend in excel.

Dave
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Jack Hogan

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Phase One Trichromatic and Standard Back D65 Matrices
« Reply #112 on: January 03, 2018, 04:56:34 pm »

BTW, raw files of those images Erik used are available here, along with others.
TCv3100 Hightail link
The last file is a legend in excel.

Thank you David.  I took the ColorChecker files for the Trichromatic and Standard Back IQ3-100 and, under the assumption that lighting is about D65 (RawTherapee says about 6480k for the Standard Back) I estimated compromise matrices for them based on average BabelColor spectral reflectance.  There are a large number of provisos and non idealities - lighting, different ISO and exposure, position of cc24 (probably resulting in contamination of some of the patches by reflectance from items in the scene), absence of direct spectral measurements, etc. - not least of which the fact that I am not a (color) scientist and often prone to embarrassing mistakes (:-) so I would take these results with a pinch of salt.  Nevertheless I think that they start to give a relative idea of some of the differences in the CFAs in the two backs.

Interestingly, with the assumptions above, the Standard Back is able to achieve better dE and dE2000: SMI is an excellent 86.7, average dE2000 is 1.49, 10 patches have dE2000 less than 1 and only 5 greater than 2.  In these conditions this is very good:



The same values for the Trichromatic are: a decent SMI of 81.1, average dE2000 of 1.87, 8 patches less than 1 dE2000 and 11 patches above 2 (  Recall that 1 dE2000 is supposed to represent a just noticeable difference).  Decent, but at first glance the SB is more accurate than the TC (shown below):



A strong hint as to what has been changed is given by the CameraNeutral values, that show that the R and B channels are more sensitive relative to G in the TC (an alternative interpretation could be that G is less sensitive, I didn't check it).  The wbRaw->XYZD65 matrices suggest that the TC is a little better at blues but the SB is a little better at reds.  The weighted sum of RGB negative coefficients suggests that the TC should have a slight advantage with noise but given the large number of differences in the setup I wouldn't put much weight on it.

Finally, here is a screen capture with the two images rendered via their relative wbRaw->sRGB matrix and nothing else, just to show that they work - I did not try particularly hard to match their brightnesses (332, left, is TC; 336, right, is SB):



And each of them individually (which is which?)*:





Jack

PS Information here may be helpful in understanding the procedure I followed to generate what's above.

* SB first, TC second.
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hubell

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #113 on: January 03, 2018, 05:19:09 pm »

I personally would ignore the numbers and look at the files with my eyes. IMO, the fruits in the files shot with the TC back look richer than the fruits in the files shot with the Standard back. The TC file has an enhanced three dimensionali quality compared to the SB file. It appears as if a veil has been lifted. What I don't know is whether the TC back file has been "cooked" in some way to add a touch of clarity or midtone contrast. It would be interesting to see if the SB file can be processed to look more like the TC file. It would also be interesting to see how Hasselblad's H6D-100 and X1D files look in comparison.

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Re: Phase One Trichromatic and Standard Back D65 Matrices
« Reply #114 on: January 03, 2018, 08:25:46 pm »

Hi Jack,

Thanks for your efforts and sharing your findings.

For me, the great difference is in the foliage greens. IQ3100MP is a bit brownish while the TC is cleaner green. My take is it may be IR/near IR contamination. Foliage reflects a lot of IR. The foliage patch on the color checker does not.

Doug Petersen suggested that lime greens would be affected. I did a simple test a few months ago, with three camera I have, an older P45+, Sony A900 which is CMOS same generation and Sony A7rII. I got 'perfect' greens on the limes I used - with all three cameras. So, I simply did not see the brown contamination in any of those shots. But, I was using electronic flash.

Best regards
Erik

Thank you David.  I took the ColorChecker files for the Trichromatic and Standard Back IQ3-100 and, under the assumption that lighting is about D65 (RawTherapee says about 6480k for the Standard Back) I estimated compromise matrices for them based on average BabelColor spectral reflectance.  There are a large number of provisos and non idealities - lighting, different ISO and exposure, position of cc24 (probably resulting in contamination of some of the patches by reflectance from items in the scene), absence of direct spectral measurements, etc. - not least of which the fact that I am not a (color) scientist and often prone to embarrassing mistakes (:-) so I would take these results with a pinch of salt.  Nevertheless I think that they start to give a relative idea of some of the differences in the CFAs in the two backs.

Interestingly, with the assumptions above, the Standard Back is able to achieve better dE and dE2000: SMI is an excellent 86.7, average dE2000 is 1.49, 10 patches have dE2000 less than 1 and only 5 greater than 2.  In these conditions this is very good:



The same values for the Trichromatic are: a decent SMI of 81.1, average dE2000 of 1.87, 8 patches less than 1 dE2000 and 11 patches above 2 (  Recall that 1 dE2000 is supposed to represent a just noticeable difference).  Decent, but at first glance the SB is more accurate than the TC (shown below):


A strong hint as to what has been changed is given by the CameraNeutral values, that show that the R and B channels are more sensitive relative to G in the TC (an alternative interpretation could be that G is less sensitive, I didn't check it).  The wbRaw->XYZD65 matrices suggest that the TC is a little better at blues but the SB is a little better at reds.  The weighted sum of RGB negative coefficients suggests that the TC should have a slight advantage with noise but given the large number of differences in the setup I wouldn't put much weight on it.

Finally, here is a screen capture with the two images rendered via their relative wbRaw->sRGB matrix and nothing else, just to show that they work - I did not try particularly hard to match their brightnesses (332, left, is TC; 336, right, is SB):


Jack

PS Information here may be helpful in understanding the procedure I followed to generate what's above.

* SB first, TC second.
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dchew

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Re: Phase One Trichromatic and Standard Back D65 Matrices
« Reply #115 on: January 03, 2018, 08:26:35 pm »

PS Information here may be helpful in understanding the procedure I followed to generate what's above.

Jack, thank you very much and very informative post.

I personally would ignore the numbers and look at the files with my eyes. IMO, the fruits in the files shot with the TC back look richer than the fruits in the files shot with the Standard back. The TC file has an enhanced three dimensionali quality compared to the SB file. It appears as if a veil has been lifted. What I don't know is whether the TC back file has been "cooked" in some way to add a touch of clarity or midtone contrast. It would be interesting to see if the SB file can be processed to look more like the TC file. It would also be interesting to see how Hasselblad's H6D-100 and X1D files look in comparison.

Howard, from my perspective and for my uses, I would say yes to your question of whether the SB file can be processed to look like the TC file. But I bet for other subjects, or other uses such as fashion, reproduction or maybe even architecture the answer might be different. Your comment about the richness / veil is interesting. I didn't notice that, but I didn't compare them with their matrixes the way Jack did.

Dave


(The water looks different because the cloud cover was slightly different for the two photos which caused a different reflection)
« Last Edit: January 03, 2018, 08:30:39 pm by dchew »
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32BT

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Re: Phase One Trichromatic In Depth Article with Raw Files
« Reply #116 on: January 03, 2018, 09:28:30 pm »

We first need to figure out what causes the colorchecker differences in Jacks experiment. The veil could be a result of the profiles generated, but then the colorchecker itself shouldn't exhibit as much difference as it does.

For me the darker blue patches and the increased red in caucasian skin is noticeable, even just side-by-side, as is the different greenish tinge in (clipped?) yellow lemons. When the images are placed on top of each other there are more differences of course.
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hubell

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Re: Phase One Trichromatic and Standard Back D65 Matrices
« Reply #117 on: January 03, 2018, 10:54:03 pm »

. Your comment about the richness / veil is interesting. I didn't notice that, but I didn't compare them with their matrixes the way Jack did.

Dave

Dave, quite frankly, I did not expect much from the TC backs compared to the already impressive files out of the IQ3 100. However, looking at the files presented here by Jack with my iPad Pro, I really am struck by the visual differences. The SB files look flat and two dimensional. The TC files look more lifelike and three dimensional. I have no idea why this difference exists. As I suggested, Phase may have worked on the default settings on import in a way that bumped the midtone contrast. I don’t know anything about color science, so it may also be that the purity of the colors has been enhanced and this in and of itself produces better color differentiation and therefore a more three dimensional look. Something is happening here, what it is ain’t exactly clear....

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Re: Phase One Trichromatic and Standard Back D65 Matrices
« Reply #118 on: January 04, 2018, 04:07:25 am »

Hi Howard,

Jack's images and data illustrate the basic differences between the sensors, using an optimized compromise matrix. So that is a basic difference between the two sensors.

Of course, having a different input needs a different approach to generating LUT (Look Up Table) based profiles. The normal approach is to use a matrix profile to convert RGBG channels into XYZ colour space and than apply LUT based corrections. It is said that Phase One uses an other approach not using compromise matrix in Capture One.

The other question is if the colour rendition can be achieved using profiling. It may seem that the IQ 3100 may not be able to yield the same colours as the Thrichromatic.

Best regards
Erik


Dave, quite frankly, I did not expect much from the TC backs compared to the already impressive files out of the IQ3 100. However, looking at the files presented here by Jack with my iPad Pro, I really am struck by the visual differences. The SB files look flat and two dimensional. The TC files look more lifelike and three dimensional. I have no idea why this difference exists. As I suggested, Phase may have worked on the default settings on import in a way that bumped the midtone contrast. I don’t know anything about color science, so it may also be that the purity of the colors has been enhanced and this in and of itself produces better color differentiation and therefore a more three dimensional look. Something is happening here, what it is ain’t exactly clear....
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Re: Phase One Trichromatic and Standard Back D65 Matrices
« Reply #119 on: January 04, 2018, 04:25:29 am »


Dave


(The water looks different because the cloud cover was slightly different for the two photos which caused a different reflection)

Seems to have the appearance of a bit of local contrast. Could there be a default/initial setting in processing that is different?
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