Luminous Landscape Forum

Equipment & Techniques => Medium Format / Film / Digital Backs – and Large Sensor Photography => Topic started by: narikin on January 19, 2018, 05:26:32 pm

Title: Getting the A7R3 files closer to IQ100 back outputs?
Post by: narikin on January 19, 2018, 05:26:32 pm
Hi all - I'm fortunate enough to own both Phase, Alpa, Canon and Sony systems, but mostly use the Alpa/Phase and Sony systems. They do different things and do them brilliantly. No need to describe the quality of MF output here, you all know it. The A73 is so incredibly clever - with its autofocus face/etc detect really working well, compared to the mk2 body. Silent, 10fpd, quick, great AF, etc, etc.

The thing is after using the IQ100, it is so hard to adjust to the Sony files - the color, resolution, dynamic range all seem very poor in comparison.
This is with good lenses - even with a $4000 Otus, it still lacks something.

so what am I doing wrong here?
I'm prepared to accept the smaller files, that is not the issue, its the quality of those files I'm finding tough to accept. Both are Sony sensors of similar generation, so why the big difference?

Thanks[/list]
Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: ErikKaffehr on January 19, 2018, 05:40:43 pm
Hi,

Could you post some examples with the issues you have, preferably with raw files. There can be quite a few problems, starting with white balance, profiles etc.

But it is hard to discuss issues that you have not seen.

Best regards
Erik
Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: BernardLanguillier on January 19, 2018, 06:08:57 pm
Have you tried using the P1 profiles for your Sony files?

Cheers,
Bernars
Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: narikin on January 19, 2018, 06:17:24 pm
Have you tried using the P1 profiles for your Sony files?

Cheers,
Bernars

P1 means... Phase One - or is there some other profile makes confusingly named P1?
I am using Capture One's own Sony profiles.


Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: ErikKaffehr on January 19, 2018, 07:08:02 pm
Hi,

Bernard has a point. It has been demonstrated earlier by some Capture One users that using profiles for the IQ350 (I think) with Nikon D800 images yielded better colour than C1-s profiles for Nikon D800.

It may be that Phase One is making better profiles for the IQ-series than for Sony for instance.

Making own colour profiles for Capture One is a bit tricky, as they use different math from conventional profiles.

But, Anders Torger has found a way to generate ICC colour profiles for Capture One in his tools DCamProf (free and open source) and Lumariver Profile Designer.

I can try to generate an ICC profile for C1 for the A7rIII based on test images from ImagingResource in the weekend. I never tried it as I am Lightroom user.

But, such a profile may or may not get IQ3100 MP and Sony A7rIII closer. It depends on weather or not they use a similar CFA design. Also, even if the profiles would yield similar results, chance may be that they would not have a Capture One kind rendition.

For some reason I did a comparison comparing three cameras I have at home.

- Phase One P45+ back, known for tricky colour.
- Sony Alpha 900, same generation as P45+ but regarded by some experts (TheSuede and Iliah Borg) to have the best rendition of any commercially available camera.
- Sony A7rII, what I am mostly using now.

I enclose the result. There are four images. Top row is P45+, with two different tone curves. Bottom row is Sony A7rII on the left and Sony Alpha 900 on the right. Note the black boxes on the lime fruits. These were measured with a spectrometer. The limes in the front and the rear and the red pepper has boxes painted in with measured colours. These areas are close but outside the red boxes.

Would be interesting to hear your opinion on how these colours differ.

Best regards
Erik



P1 means... Phase One - or is there some other profile makes confusingly named P1?
I am using Capture One's own Sony profiles.
Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: DP on January 19, 2018, 08:57:58 pm
so what am I doing wrong here?

1) comparing 100mp on a bigger sensor vs 42mp on a smaller sensor

2) both sensors are CMOS quite recent generation from Sony,  so no replacement for displacement here = http://www.photonstophotos.net/Charts/PDR.htm#Phase%20One%20IQ3%20100MP,Sony%20ILCE-7RM3

3) as for the color - create your own profiles
Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: Chris Barrett on January 19, 2018, 09:39:10 pm
Curious.  Back when the IQ3 100 came out, I spent a day shooting it with Kevin alongside my A7r2.  When you zoom in to 100%, the IQ files definitely look nicer.  I wouldn't say there is a 'huge' difference though.

Both images shot through the Rodenstock Apo Sironar Digital 45mm.

IQ3 100
(http://christopherbarrett.net/wp-content/uploads/2018/01/IQ3-100.jpg)

A7r2
(http://christopherbarrett.net/wp-content/uploads/2018/01/A7r2.jpg)


CB
Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: BernardLanguillier on January 19, 2018, 09:56:10 pm
Not too impressed by the blooming around the chandelier...

Cheers,
Bernard
Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: ErikKaffehr on January 20, 2018, 12:34:06 am
Hi all - I'm fortunate enough to own both Phase, Alpa, Canon and Sony systems, but mostly use the Alpa/Phase and Sony systems. They do different things and do them brilliantly. No need to describe the quality of MF output here, you all know it. The A73 is so incredibly clever - with its autofocus face/etc detect really working well, compared to the mk2 body. Silent, 10fpd, quick, great AF, etc, etc.

The thing is after using the IQ100, it is so hard to adjust to the Sony files - the color, resolution, dynamic range all seem very poor in comparison.
This is with good lenses - even with a $4000 Otus, it still lacks something.

so what am I doing wrong here?
  • Maybe nothing, is this just the way it is? the difference is huge, if so.
  • I know C1 reasonably well, but maybe am not processing the files correctly - is there a default Sat/Contrast/Profile I should try that transforms things?
  • Does C1 somehow hobble the camera profile for the Sony, to make themselves look better - maybe not quite as refined/polished as their own backs' profiles? Should I try a different Raw converter?
  • Build my own camera profile? Or buy an alternate one from somewhere?
  • Something else?
I'm prepared to accept the smaller files, that is not the issue, its the quality of those files I'm finding tough to accept. Both are Sony sensors of similar generation, so why the big difference?

Thanks[/list]
Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: narikin on January 20, 2018, 08:07:29 pm
Thanks all for suggestions. I don't have the ability to compare the Sony camera/ IQ back with the same exact lens.  My Alpa/XF lenses can't fit the Sony and vice-versa. Yes, there are adapters, but I don't own one at present.

My suspicion is not that Phase deliberately hobbles the A7R3 via a poor profile, but that they simply don't try as hard to refine it. A quick generic profile is created, and that's it.
Which is of course not the case with profiles for their own backs.  But... it's just a suspicion. No evidence of that, save my disappointment.
And some could argue: why should they do more for another manufacturer?

I may try some other converters. Or go hunting for a fresh C1 profile from somewhere,

Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: Chris Livsey on January 21, 2018, 04:35:54 am

My suspicion is not that Phase deliberately hobbles the A7R3 via a poor profile, but that they simply don't try as hard to refine it.

I have no horse in this race but think you do them an injustice. Many times they have stated the reason support for new cameras is delayed because of the exhaustive testing that they perform to produce compatibility and profiles. That they have an agreement with Sony and produce a Sony only version of C1, with some features reduced over the full version, would again point to them having every reason to produce an effective profile for Sony cameras. They did, a long time ago in a galaxy far, far away have a version for the Leica M8 so there is history of their collaboration, Nikon would do well to take note, and maybe they have as the D850 seems to have been supplied early to them perhaps with some engineering data?
That you find a big difference in the files is perhaps not surprising given the cost of the two systems you are comparing, if the Sony = iQ100 perfectly then Phase One would not be in business very long making digital backs, that others are satisfied with the Sony is because sometimes good enough is good enough and they may not, like you, have such a superb system to run comparisons with,"ignorance is bliss" Thomas Gray “Ode on a Distant Prospect of Eton College” (1742) or indeed "Ignorance is strength" – " Nineteen Eighty-Four"George Orwell 1949.
Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: ErikKaffehr on January 21, 2018, 05:07:02 am
Hi,

I have spent some time on generating ICC profiles for the IQ3100 based on sample images from Imaging Resource Phase One. At this stage I am pretty sure that there is a tone curve difference between A7rII rendition and IQ3100 rendition. The IQ 3100 tone curve rolls off in the highlights while the A7rIII curve does not.

Best regards
Erik


Thanks all for suggestions. I don't have the ability to compare the Sony camera/ IQ back with the same exact lens.  My Alpa/XF lenses can't fit the Sony and vice-versa. Yes, there are adapters, but I don't own one at present.

My suspicion is not that Phase deliberately hobbles the A7R3 via a poor profile, but that they simply don't try as hard to refine it. A quick generic profile is created, and that's it.
Which is of course not the case with profiles for their own backs.  But... it's just a suspicion. No evidence of that, save my disappointment.
And some could argue: why should they do more for another manufacturer?

I may try some other converters. Or go hunting for a fresh C1 profile from somewhere,
Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: Bo_Dez on January 21, 2018, 08:59:23 am
When I use medium format digital it's always a shock trying to use 35mm.
Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: Wayne Fox on January 21, 2018, 03:29:42 pm
Hi,

I have spent some time on generating ICC profiles for Phase One. At this stage I am pretty sure that there is a tone curve difference between A7rII rendition and IQ3100 rendition. The IQ 3100 tone curve rolls off in the highlights while the A7rIII curve does not.

Best regards
Erik
I assume you mean for a Phase One back, and not for Phase One? Just sounds a little odd, perhaps might confuse some?
Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: madlantern on January 21, 2018, 04:50:52 pm
Why not trying comparing both in Lightroom with the Adobe Standard profile for a more even playing field?
Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: narikin on January 21, 2018, 05:59:32 pm
When I use medium format digital it's always a shock trying to use 35mm.

My worry is that this is the problem. It seems just a huge quality gulf between the two. Quite shocking.
So much so, I'm convinced I must be doing something wrong!
Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: Doug Peterson on January 21, 2018, 07:56:40 pm
Why not trying comparing both in Lightroom with the Adobe Standard profile for a more even playing field?

I think the even playing field is to try both cameras in a variety of software that you might otherwise be comfortable with in a normal workflow, and see which combination gives you the results you like most.

When I have clients run their P1 raw files in both C1 and LightRoom 95%+ prefer the rendering in C1. That shouldn't really surprise anyone; the team that makes Phase One hardware and the team that makes Phase One software are down the hall from each other. They go to the bars together. They go on family vacation together. Where most software vendors are stuck reverse engineering the file of a camera days or week after it is produced, the P1 software team is working with the hardware team months before a new piece of hardware is released. They not only get raw files well in advance, they are part of the R+D process itself (no example of this finer than the Trichromatic (https://digitaltransitions.com/phase-one-trichromatic-part-1-the-science/) which started, in part, because of feedback from the profiling/color-science team), providing feedback on what changes/tweaks to the hardware will result in a file that they can best work with on the software/profiling side. The software team works with a huge set of real world images, controlled lab-images, and deep technical knowledge of the hardware, to produce a color profile, detail extraction algorithms, lens corrections, and other factors of "raw file support" and are given nearly carte blanche on resources (time/money) spent on getting the most out of a P1 raw file. They pull all nighters tracing down the cause of image quality defects that even very "detail oriented" photographers would consider trivial. The amount of time the two teams spend fine-tuning the result of a P1 back in C1 is truly impressive.

In my experience you cannot replicate the above by snapping a picture of a target and running it through a color profiling software.

In contrast to the deeply collaborative and intensely pursued software/hardware relationship between P1 and Capture One... in LR, a P1 back is "just another camera" – that's not to say they don't put careful effort into doing their best, but it is a different world entirely.

Bottom line: the Sony is a VERY good small-format camera (and very good from a performance per dollar value perspective). It's small and light and has good video features; it's a tremendous little camera. But I'm honestly a little confused why you'd expect it to match the image-quality performance of your 16 bit full-frame 645 Phase One camera.
Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: Doug Peterson on January 21, 2018, 08:10:06 pm
I'll venture one more analogy...

Re: P1 in LR vs P1 in C1

It's like hearing a song as a cover versus the original artist.

You should always be willing to give it a chance, and occasionally it's even better (https://www.youtube.com/watch?v=VBmCJEehYtU). But generally it should not surprise you when it's lacking some of the nuance and finesse.

When you try (as you should) the Sony in LR or the Sony in C1 with a 3rd party profile make sure to include a variety of raws shot in a variety of lighting at a variety of ISOs. When you do I think you'll find that Phase One has done a very good job with the Sony profile and that C1 produces the best out-of-camera results. But ultimately a Sony in Capture One (or LightRoom or or) is a cover song, and using profiling software is often like AutoTune – the results can seem better at first blush, but often don't have the depth or wholistic on-ness of a profile crafted by an expert.
Title: Here is what I came up with...
Post by: ErikKaffehr on January 21, 2018, 09:05:30 pm
(http://echophoto.dnsalias.net/ekr/Articles/C1Stuff/Capture.jpg)

Here is a layered tiff: http://echophoto.dnsalias.net/ekr/Articles/C1Stuff/LayeredComparison.tif

File and layer names should be quite obvious.

Best regards
Erik



Hi all - I'm fortunate enough to own both Phase, Alpa, Canon and Sony systems, but mostly use the Alpa/Phase and Sony systems. They do different things and do them brilliantly. No need to describe the quality of MF output here, you all know it. The A73 is so incredibly clever - with its autofocus face/etc detect really working well, compared to the mk2 body. Silent, 10fpd, quick, great AF, etc, etc.

The thing is after using the IQ100, it is so hard to adjust to the Sony files - the color, resolution, dynamic range all seem very poor in comparison.
This is with good lenses - even with a $4000 Otus, it still lacks something.

so what am I doing wrong here?
  • Maybe nothing, is this just the way it is? the difference is huge, if so.
  • I know C1 reasonably well, but maybe am not processing the files correctly - is there a default Sat/Contrast/Profile I should try that transforms things?
  • Does C1 somehow hobble the camera profile for the Sony, to make themselves look better - maybe not quite as refined/polished as their own backs' profiles? Should I try a different Raw converter?
  • Build my own camera profile? Or buy an alternate one from somewhere?
  • Something else?
I'm prepared to accept the smaller files, that is not the issue, its the quality of those files I'm finding tough to accept. Both are Sony sensors of similar generation, so why the big difference?

Thanks[/list]
Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: narikin on January 21, 2018, 09:07:19 pm
I'll venture one more analogy...

Re: P1 in LR vs P1 in C1

It's like hearing a song as a cover versus the original artist.

You should always be willing to give it a chance, and occasionally it's even better (https://www.youtube.com/watch?v=VBmCJEehYtU). But generally it should not surprise you when it's lacking some of the nuance and finesse.


Thanks for the input Doug. And for Puddles Pity Party, which was great to listen to, but nope, not better!

Have to point out it's moot who's the original and who's the cover version when it comes to sensors and processing. Sony make the sensors, as you very well know. Not Phase. Yes, Phase do great things with them, but Sony is the original manufacturer, and have the engineers & scientists in house. So...

And to clarify: I'm not expecting it to be the same, I just was expecting a smaller resolution version of the MF files, but: nope. That's what's confusing (and saddening) me. These are not competitive products, they complement each other quite perfectly otherwise, I'd love for the output files to be broadly comparable other than scale, but I just can't get there. Sigh.
Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: ErikKaffehr on January 21, 2018, 09:17:56 pm
Hi,

I guess that "Narikin" perhaps wants to be able to mix images shot with the different cameras.

You are probably right. I did a lot of experimenting on the samples I downloaded from Imaging Resource.

Best regards
Erik


...
Bottom line: the Sony is a VERY good small-format camera (and very good from a performance per dollar value perspective). It's small and light and has good video features; it's a tremendous little camera. But I'm honestly a little confused why you'd expect it to match the image-quality performance of your 16 bit full-frame 645 Phase One camera.
Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: ErikKaffehr on January 21, 2018, 09:20:29 pm
Hi Wayne,

Sloppy use of language. Thanks for making the point!

Best regards
Erik

I assume you mean for a Phase One back, and not for Phase One? Just sounds a little odd, perhaps might confuse some?
Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: narikin on January 21, 2018, 09:22:13 pm
Thanks Erik,

Well, exactly.

Open this layered TIFF in ps, select the base layer IQ3100, then toggle on off layer #3 - the A7R3 Generic - and watch the yarn rainbow weaken dramatically.

Why so? It's beyond my knowledge to offer an answer. The sensor is same generation roughly, smaller of course, same C1 processing, so why does the color drop away?
Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: Doug Peterson on January 21, 2018, 09:23:38 pm
Thanks for the input Doug. And for Puddles Pity Party, which was great to listen to, but nope, not better!

Have to point out it's moot who's the original and who's the cover version when it comes to sensors and processing. Sony make the sensors, as you very well know. Not Phase. Yes, Phase do great things with them, but Sony is the original manufacturer, and have the engineers & scientists in house. So...

The analogy is imperfect (as most analogies are).

A [Camera] is much more than a [Sensor]. Sony through C1 or LR is not as "native" as P1 through C1.


And to clarify: I'm not expecting it to be the same, I just was expecting a smaller resolution version of the MF files, but: nope. That's what's confusing (and saddening) me. These are not competitive products, they complement each other quite perfectly otherwise, I'd love for the output files to be broadly comparable other than scale, but I just can't get there. Sigh.

It's a very reasonable assumption to make that small-format Sony is just like medium-format Phase, just smaller. It's concise. It's logical to some extent.

Unfortunately it's just not true. As you're finding, Phase One has both hardware/software/profiling under one roof and prioritizes image quality over all else, and it shows in the end result.
Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: ErikKaffehr on January 21, 2018, 10:00:36 pm
Hi,

If you enable layer two, that is A7rIII_EKr and toggle layer 3 that is A7rIII_C1_Generic you can see the difference caused by profiles.

You can repeat the experiment using layer 1 (IQ3100 with C1 flash profile) and layer 4 (the Lumariver profile I generatted for the IQ3100MP).

So profiles matter...

We can compare colour rendition between Sony A7rIII and IQ3100MP if we activate layer 2 and layer 4 and toggle layer 4. Those are both using my profile. So that should be an estimate for the colour differences in sensor CFAs.

Best regards
Erik

Thanks Erik,

Well, exactly.

Open this layered TIFF in ps, select the base layer IQ3100, then toggle on off layer #3 - the A7R3 Generic - and watch the yarn rainbow weaken dramatically.

Why so? It's beyond my knowledge to offer an answer. The sensor is same generation roughly, smaller of course, same C1 processing, so why does the color drop away?
Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: algrove on January 22, 2018, 01:40:03 am
I know others besides myself who are not pleased with Sony A7R3 results when comparing IQ3100 files versus a7R3 files. Double the resolution and another $40k must do something to make them better files. Let's hope so anyway.
Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: Jack Hogan on January 22, 2018, 06:05:18 am
Thanks Erik,

Well, exactly.

Open this layered TIFF in ps, select the base layer IQ3100, then toggle on off layer #3 - the A7R3 Generic - and watch the yarn rainbow weaken dramatically.

Why so? It's beyond my knowledge to offer an answer. The sensor is same generation roughly, smaller of course, same C1 processing, so why does the color drop away?

The reason is quite simple: a good many of the tones in the yarn (and the fabric elsewhere) are out of gamut in both cameras in Adobe RGB - so it's a crapshoot as to what the original colors looked like.  Other than that both cameras show a comparable color accuracy score under this artificial D50 light (SMI of about 86).

Jack
Title: Out of Gamut
Post by: Jack Hogan on January 22, 2018, 08:51:10 am
And here are the Adobe RGB out-of-gamut images: the colors refer to the channel that is blocked (R,G, B - white means highlight clipping).  There are 473K tones blocked in the IQ3-100 vs 173K in the a7rIII, I would call it even given the different file sizes.  The latter appears to be slightly better in the yellow hues while the former in the reds.  As mentioned earlier, as far as in-gamut tones are concerned the two cameras appear to be about equivalent.

(https://i.imgur.com/GkiSReR.gif)

So viewing these D50 captures one really seems to learn more about how the relative profiles choose to paint-in out-of-gamut tones rather than the true capabilities of the hardware.  Operator error is always a possibility where I am concerned but I wonder if anyone has ever raised this issue with IR.

Jack
Title: Re: Out of Gamut
Post by: Doug Peterson on January 22, 2018, 09:21:20 am
And here are the Adobe RGB out-of-gamut images

Why would you measure the in-gamut and out-of-gamut in the images converted to Adobe RGB. Would it not make more sense to look at the files in their respective original color space (C1 allows you to embed the original profile when outputting to TIFF or JPG to facilitate such investigations).
Title: Re: Out of Gamut
Post by: Jack Hogan on January 22, 2018, 10:28:51 am
Why would you measure the in-gamut and out-of-gamut in the images converted to Adobe RGB. Would it not make more sense to look at the files in their respective original color space (C1 allows you to embed the original profile when outputting to TIFF or JPG to facilitate such investigations).

Hello Doug,

Because I thought 99% of the folks here would be trying to judge color in these images by looking at them on their monitors, 99% of which only cover Adobe RGB or less.  So here is a question: why would a commercial site have a target with so much of it outside of Adobe RGB?  I can't imagine what the vast majority of people - with sRGB coverage at best - think they are judging as far as color is concerned ;-)

And I am not sure what the original color space of the files is.  My images are rendered 100% linearly with no adjustments/profiles whatsoever by multiplying the white balanced raw data by the optimized compromise color matrix for the individual capture as setup.  Then counting blocked (less than zero, out-of-gamut) and clipped (specular highlights in this case) pixels in the chosen destination color space.  The beauty of the linear color approach is that it speaks quantitatively to the capabilities of the hardware - before profiles and qualitative processing enter the picture to make up for its weaknesses and/or produce more pleasing results.  Which doesn't mean that as a landscape photographer I do not appreciate a well researched, robust profile to render pleasing images with a minimum of fuss.  But when trying to measure the capabilities of the hardware, profiles take a back seat.

Jack
Title: Re: Out of Gamut
Post by: 32BT on January 22, 2018, 10:48:31 am
My images are rendered 100% linearly with no adjustments/profiles whatsoever by multiplying the white balanced raw data by the optimized compromise color matrix for the individual capture as setup. 

But how do you set the multipliers? If you take the white patch and map it linear to 90% then the consequence is that a lot of other colors might get clipped by simple overexposure due to method, and not by colorconversion. It seems rather odd that the yarn would be out-of-adobegamut...
Title: Re: Out of Gamut
Post by: Jack Hogan on January 22, 2018, 11:10:21 am
But how do you set the multipliers? If you take the white patch and map it linear to 90% then the consequence is that a lot of other colors might get clipped by simple overexposure due to method, and not by colorconversion. It seems rather odd that the yarn would be out-of-adobegamut...

Hi Oscar,

I know, I was surprised myself about the yarn. I went through all this because I was flipping back and forth on the images of the yellow thread in PS (my render) and I noticed that blue was showing  a lot of zero values.  Then I looked around and I saw a lot more blocked tones.  The process I follow is outlined in this article (http://www.strollswithmydog.com/determining-forward-color-matrix/).  The routine spits out the optimized matrix for the white balanced raw data as-is and it can be used as-is.  It assumes that the third CC neutral patch from the right has its published value of about L*=50, a*=0, b*=0.  In this case only specular reflections are clipped.  If brightness is reduced by a stop before applying the matrix the out of gamut values remain virtually unchanged.

Jack

BTW the lighting is different in character in the two images, you can see that in the shadows.  One is more diffuse than the other.
Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: Doug Peterson on January 22, 2018, 11:24:28 am
What colors are in/out of gamut in the original raw file (in the original profile) is what really matters.

A savvy user can then decide whether and in what way to ensure the final output file is within gamut for a given use in a given profile (sRGB, Adobe 1998, ProPhoto, a particular printer etc).

Assuming of course your worried about the practical rather than the academic.
Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: Jack Hogan on January 22, 2018, 12:10:21 pm
What colors are in/out of gamut in the original raw file (in the original profile) is what really matters.

I am not familiar with C1 or its terminology Doug.  The 'original' profile I assume is the Profile Connection Space, i.e. XYZ, so if the colors are known to be out of Adobe RGB gamut while there and one wishes to finally display the image in such a color space then someone, manually or automatically, needs to physically take the out-of-gamut tones and bring them in-gamut - because it's better to smooth out the blocking, right?  And the instant one starts twisting tones around by applying a profile one loses the ability to say that one camera's color is better than another by looking at the rendered image: too many changes applied, designed to give a certain 'look', sometimes far removed from the tones actually produced by the sensor.  Of course one can say anything anecdotally, as in 'I prefer the way C1 renders my raw files than LR'.

On the other hand to be able to say that one camera produces better color than another one needs to roll up one's sleeves and look under the hood where the engine can be seen running before the profile is applied.  But I know you know all this, having watched some of your webinars :)

Jack
Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: ErikKaffehr on January 22, 2018, 12:24:04 pm
Hi Jack,

Thanks for that info. I have tested generating som ICC profiles with LumaRiver profile designer, and my files are quiet similar using the LumaRiver profiles.

I have also noticed that the test target is similar but not identical.

So, what I see is IQ3100 is pretty similar to A7rII with profiles generated by Lumariver but quiet different with the "Generic" profile built into C1. Sort of indicates that hardware capabilities are similar, except the IQ3100MP sensor being larger and having more pixels but the profiles by Phase One are different.

If I use a colour profile generated by LumaRiver with Capture One or LR, I get similar colours except on the blue yarn.

Best regards
Erik

The reason is quite simple: a good many of the tones in the yarn (and the fabric elsewhere) are out of gamut in both cameras in Adobe RGB - so it's a crapshoot as to what the original colors looked like.  Other than that both cameras show a comparable color accuracy score under this artificial D50 light (SMI of about 86).

Jack
Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: DougDolde on January 22, 2018, 12:46:45 pm
I don't know about Sony or the 100 megapixel Phase One backs but I sold off my IQ180, body and lenses and replaced them with a Nikon D850 and three Zeiss ZF.2 lenses, 21mm, 28mm and 85mm.

I am blown away with the quality. Sure it's less resolution but it's plenty.  The DR, low light capability, Live View focus peaking, and it's much lighter weight and field friendly. 

Plus I can still process the files in Capture One Pro.  The total outlay was just under $6000

Take that Phase One
Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: Jack Hogan on January 22, 2018, 01:18:04 pm
So, what I see is IQ3100 is pretty similar to A7rII with profiles generated by Lumariver but quiet different with the "Generic" profile built into C1. Sort of indicates that hardware capabilities are similar, except the IQ3100MP sensor being larger and having more pixels but the profiles by Phase One are different.

Ok, makes sense, thanks Erik.  BTW I checked DPR's D65 studio scene with a a7Riii capture and it's a different story.  Just a few bits here and there are out of aRGB gamut (some paint tubes etc.) but most of it is in-gamut.
Title: Re: Getting the A7R3 files closer to IQ100 back outputs?
Post by: ErikKaffehr on January 22, 2018, 05:10:25 pm
Hi Jack,

These images have been converted to sRGB, in order to simplify viewing in browsers:

First, IQ3100 processed in C1 with Flash profile:
(http://echophoto.dnsalias.net/ekr/Articles/C1Stuff/IQ3100_C1_srgb.jpg)

Next is same image, but processed in C1 with a LumaRiver profile:
(http://echophoto.dnsalias.net/ekr/Articles/C1Stuff/IQ3100_D50_Ekr.jpg)

Up next is A7rIII processed in C1 with a Lumariver profile:
(http://echophoto.dnsalias.net/ekr/Articles/C1Stuff/A7rIII_D50_EKr.jpg)

The last one is A7rIII processed with C1-s built in profile (ArrIII generic):
(http://echophoto.dnsalias.net/ekr/Articles/C1Stuff/A7rIII_C1.jpg)

The differences are much more obvious if you stack the images in Photoshop:

http://echophoto.dnsalias.net/ekr/Articles/C1Stuff/LayeredComparison.tif

Best regards
Erik

Ok, makes sense, thanks Erik.  BTW I checked DPR's D65 studio scene with a a7Riii capture and it's a different story.  Just a few bits here and there are out of aRGB gamut (some paint tubes etc.) but most of it is in-gamut.