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Author Topic: Dual Illuminant Profiles  (Read 39152 times)
opgr
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« Reply #60 on: May 15, 2012, 01:13:50 PM »
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I don’t know Eric is trying to correct anything but rather initially describe. This is supposed to work in a raw converter which doesn’t circumvent rendering to taste.

I understand. Using a monochromator for characterizing a camera may be useful. Capturing an on-scene spectrum currently has little or no meaning, neither for image processing, nor for the photographer.

Just to think about it without going too much into technical detail, but if you capture an on-scene spectrum, does it represent the scene average, weighted average, or perhaps point metering value? Does that point-metering value represent the actual light, the on-scene lighting condition, something else? Can the resulting spectrum or its derived tri-color be used for gray balancing? Would it yield a different result if the tri-color was derived by conventional methods?

Would a photographer that actual needed such precision perhaps be helped by simply carrying a spectrophoto meter?

I'm just wondering. I'm not in particular questioning what Eric W and the others are developing here. Do you know the current status of those developments are?

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Oscar Rysdyk
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« Reply #61 on: May 15, 2012, 01:43:25 PM »
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Capturing an on-scene spectrum currently has little or no meaning, neither for image processing, nor for the photographer.
No but I think Eric is using that to build a unique on-the-fly profile using that data. That and the spectral sensitivities of the chip are key to his creating this ‘profile’ of camera+scene if I’m explaining his concept correctly. The photographer doesn’t have any access to this metadata nor do they need it.

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Do you know the current status of those developments are?
I’m sure it has been proposed through the ICC and the committee Eric is on but other than that, I don’t know that anything as progress since that post 4 years ago. Heck, look how long we’re waiting on actual V4 ICC support.
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Andrew Rodney
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Tim Lookingbill
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« Reply #62 on: May 15, 2012, 02:29:30 PM »
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Oscar, I saw your "Sunny" lit CC chart samples and I have to say your camera and/or your ACR/LR settings are definitely different compared to the results I get working with my Pentax K100D DSLR. I don't have your skin tone and neutral gray issues using a sunlit CC chart source to build my profile.

The biggest problem I have in getting low Delta E readings applying the final profile to the source CCchart primarily centers around contrast induced saturation issues amplified by using ACR's default settings of Medium Tone Curve and 25 Contrast. Luminance goes off by as much as 7L, some less than others, on almost all patches.

I have to pick either setting Contrast to '0' or setting Medium Tone Curve to Linear but not both to get more accurate Luminance numbers.
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mac_paolo
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« Reply #63 on: May 25, 2012, 06:16:43 PM »
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I'm trying to chose which one is better to create a DNG profile between Xrite's Lightroom plugin and DNG Profile Editor by Adobe.
They are so different in color rendition. The whole "calibration" term doesn't seem to fit well. I mean, how can the both be valid profiles?  Roll Eyes

Here they are...

#1
-removed-

#2
-removed-

Which one do You think is the most accurate? I'll keep my opinion for the last. Smiley
« Last Edit: May 26, 2012, 02:21:51 AM by mac_paolo » Logged
sandymc
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« Reply #64 on: May 26, 2012, 01:41:10 AM »
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I'm trying to chose which one is better to create a DNG profile between Xrite's Lightroom plugin and DNG Profile Editor by Adobe.
They are so different in color rendition. The whole "calibration" term doesn't seem to fit well. I mean, how can the both be valid profiles?  Roll Eyes

Which one do You think is the most accurate? I'll keep my opinion for the last. Smiley

White balance is different between the two shots; no way to compare.

Sandy
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mac_paolo
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« Reply #65 on: May 26, 2012, 02:02:09 AM »
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White balance is different between the two shots; no way to compare.

Sandy
I'm pretty sure I set the WB for both of the version by clicking on the second grey patch from left.
I'll check again later. Smiley
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mac_paolo
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« Reply #66 on: May 26, 2012, 02:25:35 AM »
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White balance is different between the two shots; no way to compare.

Sandy
You're right. The first one way quite a bit off balance.
I regenerated the AdobeRGB preview and reimported right away into Lightroom. Trying to re-balance the previews I found that they where still a bit off, but nothing to worry about.

#1  (Temp: 2500 K, Tint: +15)


#2  (Temp: 2550 K, Tint: +15)


Which one do you prefer, now? Smiley
« Last Edit: May 26, 2012, 02:28:01 AM by mac_paolo » Logged
sandymc
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« Reply #67 on: May 26, 2012, 03:02:50 AM »
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Which one do you prefer, now? Smiley

Well, "prefer" is personal choice. I can tell you that the second one is technically much more accurate compared to a synthetic GM24 image. Especially in the reds.

Sandy
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mac_paolo
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« Reply #68 on: May 26, 2012, 04:04:02 AM »
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Well, "prefer" is personal choice. I can tell you that the second one is technically much more accurate compared to a synthetic GM24 image. Especially in the reds.

Sandy
The term "prefer" comes from the fact that none is perfect, but one is more similar to the target than the other.
I agree with you: the second one is better.
#1 -> Xrite Plugin
#2 -> DNG Profile Editor

I didn't expect so much difference here. I relied a lot to the easier Xrite solution. I'll rebuild all the profiles in the double flavor and make a choice.
I still have to test the dual illuminant DNG Profile, but for the single illuminant, DNG Profile Editor is my choice.
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Schewe
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« Reply #69 on: May 26, 2012, 02:26:26 PM »
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I didn't expect so much difference here. I relied a lot to the easier Xrite solution. I'll rebuild all the profiles in the double flavor and make a choice.

The X-rite solution is fast and easy, the DNG Profile Editor is geeky and complicated but more powerful and in my experience more "accurate"...but either solution is better than using one of the canned DNG profiles _IF_ your particular camera is different than the one Adobe tested to make the DNG profiles for ACR/LR.

Personally, there have only been a couple of times I have _HAD_ to make DNG profiles and they were done because the camera back I was using only had "preliminary" support in ACR/LR.

I have used DNG Profile Editor more than the Passport software. When I was doing the profiles for my P-65+ back, the Passport software couldn't accept the 60 MP P-65+ capture-it hung.m So, I used the DNG Profile Editor.

I've used the editor to tweak some profiles and make some specialty profiles but for most of my cameras I really don't feel the need to use anything other tan Adobe Standard...
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mac_paolo
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« Reply #70 on: May 26, 2012, 02:37:12 PM »
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The X-rite solution is fast and easy, the DNG Profile Editor is geeky and complicated but more powerful and in my experience more "accurate"...but either solution is better than using one of the canned DNG profiles _IF_ your particular camera is different than the one Adobe tested to make the DNG profiles for ACR/LR.

Personally, there have only been a couple of times I have _HAD_ to make DNG profiles and they were done because the camera back I was using only had "preliminary" support in ACR/LR.

I have used DNG Profile Editor more than the Passport software. When I was doing the profiles for my P-65+ back, the Passport software couldn't accept the 60 MP P-65+ capture-it hung.m So, I used the DNG Profile Editor.

I've used the editor to tweak some profiles and make some specialty profiles but for most of my cameras I really don't feel the need to use anything other tan Adobe Standard...
I agree and thanks for the response. I tested 4 different artificial light settings, i.e. four rooms in my home Smiley
There are mixed light with tungsten, alogen and God only know what else. The Adobe Standard was way off each and every single time.
FWIW, I almost never felt that Adobe Standard could work for me, even in daylight situations. Are we sure that Adobe Standard is the CC24 dual illuminant profile or just an average not-to-bad-in-every-condition profile?
I like to start from scratch while working on my photos. These DNG Profile Editor profiles seems to me the bast way to achieve that. Smiley
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Schewe
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« Reply #71 on: May 26, 2012, 02:50:36 PM »
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Are we sure that Adobe Standard is the CC24 dual illuminant profile or just an average not-to-bad-in-every-condition profile?

We are sure that the Adobe Standard profile for cameras are very accurate dual-illuminant profiles that are hand tuned by Eric Chan or Thomas Knoll using tools and software well beyond DNG Profile Editor (which Eric wrote). But, it's based on a very small number of camera samples (usually just one) and statistically, there is no way for Eric to know where that camera falls in the range of thousands of cameras that a particular model may sell. Generally, in beta testing Eric will find out if certain DNG profiles are a problem–usually by getting additional sample files from users. But it's been my experience that at least for my cameras (with the exception of the Phase backs) Adobe Standard is fine.
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mac_paolo
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« Reply #72 on: May 26, 2012, 04:51:12 PM »
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We are sure that the Adobe Standard profile for cameras are very accurate dual-illuminant profiles that are hand tuned by Eric Chan or Thomas Knoll using tools and software well beyond DNG Profile Editor (which Eric wrote). But, it's based on a very small number of camera samples (usually just one) and statistically, there is no way for Eric to know where that camera falls in the range of thousands of cameras that a particular model may sell. Generally, in beta testing Eric will find out if certain DNG profiles are a problem–usually by getting additional sample files from users. But it's been my experience that at least for my cameras (with the exception of the Phase backs) Adobe Standard is fine.
You obviously know much more than me. I own a D300 and previously owned a D40. Adobe standard is quite washed out, if you understand what I'm trying to explain. Not a huge deal for "easy" well lit daylight scenes; a lot worse for more difficult scenes; almost unusable for those artificial lights with non full spectrum.
Maybe it's just my bad luck, and both of my DSLRs have very different sensors from those that Eric and his collegues managed to test.
Just my .02€ Smiley
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deejjjaaaa
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« Reply #73 on: May 29, 2012, 01:41:40 PM »
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Are we sure that Adobe Standard is the CC24 dual illuminant profile or just an average not-to-bad-in-every-condition profile?

read this thread -> http://forums.adobe.com/thread/780605?tstart=180

they were less than perfect before and not all of them are perfect now (that is w/o hand-tuning of the standard profile for you own purposes).

PS: but very few people can do a generic profile better...
« Last Edit: May 29, 2012, 01:44:49 PM by deejjjaaaa » Logged
Schewe
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« Reply #74 on: May 29, 2012, 02:00:22 PM »
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they were less than perfect before and not all of them are perfect now (that is w/o hand-tuning of the standard profile for you own purposes).

For the most part that thread dealt with vender matching DNG profiles not Adobe Standard profiles...primarily for Nikon cameras. And as can be seen, the elves are still fine tuning and improving as time allows.
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deejjjaaaa
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« Reply #75 on: May 30, 2012, 12:01:23 PM »
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And as can be seen, the elves are still fine tuning and improving as time allows.

exactly the point ! but makes one to wonder why such outfit as Adobe Labs does that "as time allows" instead of procuring somebody to do that on a full time basis.
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Schewe
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« Reply #76 on: May 30, 2012, 12:08:12 PM »
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...but makes one to wonder why such outfit as Adobe Labs does that "as time allows" instead of procuring somebody to do that on a full time basis.

Eric is only one guy (I don't think Thomas does any profiling any more though he could pitch in). As to why it's hard for Adobe to get engineers, well, there aren't a lot as talented and hard working as the ACR team which is actually very small. As for the comment "as time allows" I mean that...they just released ACR 7.1 LR 4.1 which occupied a lot of time recently.

And personally, I do not really care about vender matching profiles since I use either custom or Adobe Standard. I really couldn't care less what the camera makers think is a "look", ya know?
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