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Tony Beach

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Histograms and Raw
« Reply #20 on: December 27, 2009, 12:26:11 am »

Quote from: ChuckZ
Per a posting I read somewhere recently, they said that even if you are shooting raw, the camera histogram is based on the result you would get if you are shooting jpg.

Surely enough, while the histogram in Lightroom is not exactly what I see on the camera display, it is pretty close and definitly closer than when I was using the camera defaults.

WB changes the results more than any other setting.  Research uni-WB and install it on your D300 for the most accurate histogram and determining  whether or not you are attaining optimum exposures.
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bjanes

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« Reply #21 on: December 27, 2009, 08:55:42 am »

Quote from: ChuckZ
Per a posting I read somewhere recently, they said that even if you are shooting raw, the camera histogram is based on the result you would get if you are shooting jpg.

Surely enough, while the histogram in Lightroom is not exactly what I see on the camera display, it is pretty close and definitly closer than when I was using the camera defaults.

Quote from: Tony Beach
WB changes the results more than any other setting.  Research uni-WB and install it on your D300 for the most accurate histogram and determining  whether or not you are attaining optimum exposures.

While the WB does have a huge effect on the histogram, one should not ignore the tone curve, either in the JPEG review or the rendering in ACR or Lightroom. With most subjects containing a balance of colors, the Green component of the camera RGB histogram will give the best estimate of ETTR exposure, since the green white balance multiplier is unity, while the red and blue multipliers are greater than unity. If the subject contains saturated red and blue (such as in pictures of some flowers), these channels may appear blown in the camera histogram while they are intact in the raw file because the red or blue multiplier results in overflow in those channels.

A hot camera tone curve may also cause the histogram to be too far to the right, and this effect can be more important than WB in some cases. For example, here are snapshots taken in my back yard with the Nikon D3 using the Standard Picture Control (normal contrast and saturation) rendering into Adobe RGB with daylight WB and UniWB. In the daylight WB shot, the exposure appears reasonably to the right. Since it was overcast, the picture is blueish. The UniWB histogram gives a better idea of the raw values for the red and blue channels, but this information does not aid in ETTR since the red and blue are to the left of green.

Daylight WB:
[attachment=18916:DaylightWB.jpg]

UniWB:
[attachment=18917:UniWB.jpg]

The ACR histogram with default settings appears reasonably exposed:
[attachment=18918:ACR_daylight.png]

However, if we look at the raw histogram with Rawnalize, the image is about one stop underexposed:
[attachment=18919:Rawnalize.png]

Both the camera and ACR are using a hot tone curve. In ACR an exposure offset of +0.5 stops is used, moving the histogram to the right by this amount. To get an ACR histogram better reflecting the raw data, one should set the tone curve to linear (all sliders on the main tab set to zero and the point curve set to linear) and look at the UniWB shot using -0.5 EV expose to cancel out the exposure offset that ACR uses. This histogram is still to the right of the Rawnalize histogram, since the ACR is using a gamma of 2.2.
[attachment=18920:ACR_as_shot.png]

For a better comparison, we need to convert the gamma to 1.0 and look at the histogram in Photoshop:
[attachment=18921:PS_linea...omposite.png]
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Tony Beach

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« Reply #22 on: December 27, 2009, 12:58:14 pm »

Quote from: bjanes
While the WB does have a huge effect on the histogram, one should not ignore the tone curve,
Naturally, settings should be set to zero and a linear curve installed.  I wasn't arguing that they were mutually exclusive.

Quote
A hot camera tone curve may also cause the histogram to be too far to the right, and this effect can be more important than WB in some cases. For example, here are snapshots taken in my back yard with the Nikon D3 using the Standard Picture Control (normal contrast and saturation) rendering into Adobe RGB with daylight WB and UniWB. In the daylight WB shot, the exposure appears reasonably to the right. Since it was overcast, the picture is blueish. The UniWB histogram gives a better idea of the raw values for the red and blue channels, but this information does not aid in ETTR since the red and blue are to the left of green.
It does aid some since you have about a half a stop more headroom indicated in the histogram (green channel's distance from the right side) in the uni-WB shot compared to the Daylight WB shot (where the blue channel is all the way to the right).  Lowering contrast, saturation, and even sharpening (sharpening can add as much as a third of stop) all are important to getting the histogram as close as possible to accurately reflecting the RAW data.  Also, the Standard Picture Control color profile is problematic, I use Neutral Picture Control on my D300.

Quote
Both the camera and ACR are using a hot tone curve. In ACR an exposure offset of +0.5 stops is used, moving the histogram to the right by this amount. To get an ACR histogram better reflecting the raw data, one should set the tone curve to linear (all sliders on the main tab set to zero and the point curve set to linear) and look at the UniWB shot using -0.5 EV expose to cancel out the exposure offset that ACR uses. This histogram is still to the right of the Rawnalize histogram, since the ACR is using a gamma of 2.2.
Generally with moderate contrast scenes, if you are not applying negative EC in the RAW converter and/or reducing the Brightness slider, you are working with an underexposed NEF file.
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bjanes

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« Reply #23 on: December 27, 2009, 04:40:46 pm »

Quote from: Tony Beach
Naturally, settings should be set to zero and a linear curve installed.  I wasn't arguing that they were mutually exclusive.
You can set a linear tone curve with ACR, but with the D3 camera there is no way to set a linear tone curve on the camera. At the lowest contrast (minus 3), the camera still applies a strong S curve to the data. A linear TRC would appear very flat and unattractive. Here is the lowest contrast TRC on the D3. Note that the three quarter tones are lifted upwards towards clipping.

[attachment=18923:D3_Stouf...d_Step_3.png]

Quote from: Tony Beach
Lowering contrast, saturation, and even sharpening (sharpening can add as much as a third of stop) all are important to getting the histogram as close as possible to accurately reflecting the RAW data.
Lowering the contrast does not affect the extreme highlights, but it does affect the quarter tones and three quarter tones. If you change the contrast and the highlights are affected, you are looking at the upper three quarter tones and not the highlights themselves. As shown in the above characteristic curve at the weakest contrast for the D3, the three quarter tones are not far from the clipping point. The effect of a strong contrast curve in ACR is shown below. The three quarter tones are lifted and the quarter tones are lowered, but the clipping point of the highlights and blacks is not affected. At the clipping point, input of 255 equals the output of 255. Sharpening can lift the highlights above clipping along a transition, but would not affect flat areas such as shown here. If your sharpening halos lift the highlights by 0.3 EV, you are likely oversharpening.

[attachment=18929:05_AC.PNG]

Quote from: Tony Beach
Generally with moderate contrast scenes, if you are not applying negative EC in the RAW converter and/or reducing the Brightness slider, you are working with an underexposed NEF file.
With ACR that is false if you are using the appropriate baseline offset and a linear tone curve. Here is a Stouffer wedge with highlight clipping in the green channel at step 4 as shown by Rawnalize:

[attachment=18924:O5_rawValues.png]

And here is the ACR view with the BaselineExposure offset of +0.5 taken into account by setting exposure to -0.5 EV and setting the TRC to linear. The clipping point is dead on.

[attachment=18925:05_nominal_linear.png]

Setting the contrast to Minus 50 and Plus 100 does not change the clipping point.

Contrast Minus 50:
[attachment=18926:05_contr_minus90.png]

Contrast +100:
[attachment=18927:05_contr_plus100.png]

I think you need to study the behavior of ACR and your camera JPEG engine in a bit more detail. I will leave it to you to demonstrate the behavior of the camera JPEG engine. My own studies indicate that the D3 uses a hot tone curve.
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Tony Beach

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« Reply #24 on: December 27, 2009, 06:14:27 pm »

Quote from: bjanes
You can set a linear tone curve with ACR, but with the D3 camera there is no way to set a linear tone curve on the camera. At the lowest contrast (minus 3), the camera still applies a strong S curve to the data. A linear TRC would appear very flat and unattractive.
You are mistaken.  You can apply a linear curve to the D3 using the Picture Control editing utility in NX.  Many of us have such a linear curve installed in our Nikon cameras.

Quote from: Tony Beach
Generally with moderate contrast scenes, if you are not applying negative EC in the RAW converter and/or reducing the Brightness slider, you are working with an underexposed NEF file.
Quote
With ACR that is false if you are using the appropriate baseline offset and a linear tone curve.
ACR is not the only RAW converter, nor would I consider it the best; in fact, it is my least used choice for NEF files.  Also, you refer to "offset and linear tone curve" which I presume means you are not using the Default ACR settings, which do require adjustment on optimally exposed NEF files:



Quote
And here is the ACR view with the BaselineExposure offset of +0.5 taken into account by setting exposure to -0.5 EV and setting the TRC to linear. The clipping point is dead on.
Then you agree that setting EC to a negative value is appropriate, even with ACR.

Quote
Setting the contrast to Minus 50 and Plus 100 does not change the clipping point.
Changing contrast in the Picture Controls changes the histogram; that is a distinctly separate issue from how to adjust the files using ACR (or any other RAW converter).  This was supposedly a discussion about optimal exposure settings in-camera, not about RAW conversion settings.

Quote
I think you need to study the behavior of ACR and your camera JPEG engine in a bit more detail. I will leave it to you to demonstrate the behavior of the camera JPEG engine. My own studies indicate that the D3 uses a hot tone curve.
I'm intimately familiar with the JPEG engine in Nikon's DSLRs, and how that effects the histograms derived therefrom.  I'm really not interested in doing a tutorial right now (maybe later), you might want to Google this topic and research it some more.  Here for instance, is a quick explanation of how to install the linear curve on your D3 (or other Nikon DSLR that uses Picture Controls):  http://www.clcarder.com/Tutorials/NikonCur...structions.html
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bjanes

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« Reply #25 on: December 27, 2009, 09:27:56 pm »

Quote from: Tony Beach
You are mistaken.  You can apply a linear curve to the D3 using the Picture Control editing utility in NX.  Many of us have such a linear curve installed in our Nikon cameras.
Yes, I am familiar with the Picture Control Utility. Thanks for the reference. However, concerning its effect, see below. Fortunately, one does not have to use NX to access the Picture Control Utility (See here).

Quote from: Tony Beach
ACR is not the only RAW converter, nor would I consider it the best; in fact, it is my least used choice for NEF files.  Also, you refer to "offset and linear tone curve" which I presume means you are not using the Default ACR settings, which do require adjustment on optimally exposed NEF files:
Opinions vary on NX and NX2. While it produces excellent results, the interface is awkward and it is quite slow. I had NX but did not update to NX2. When I migrated to 64 bit Win 7, I did not bother trying to install NX. I find ACR best for my needs.

Quote from: Tony Beach
Then you agree that setting EC to a negative value is appropriate, even with ACR.
Correcting for the BaselineExposure (DNG Specification) is not negative exposure compensation. See the PDF for an explanation of BaselineExposure. The proper setting for exposure without compensation produces a rendered pixel value for the highlights of 255 in 8 bit notation. With ACR one must use -0.5 EV and a linear TRC to get the proper highlight value, i.e. a 14 bit raw value at saturation (around 16000) is 255 in the rendered file. Negative exposure correction, properly speaking, is highlight recovery.

Quote from: Tony Beach
Changing contrast in the Picture Controls changes the histogram; that is a distinctly separate issue from how to adjust the files using ACR (or any other RAW converter).  This was supposedly a discussion about optimal exposure settings in-camera, not about RAW conversion settings.
A contrast curve in a raw converter works the same whether one is using the EXPEED JPEG engine, ACR, or NX2. I used ACR because that is what I use for my work.

Quote from: Tony Beach
I'm intimately familiar with the JPEG engine in Nikon's DSLRs, and how that effects the histograms derived therefrom.  I'm really not interested in doing a tutorial right now (maybe later), you might want to Google this topic and research it some more.  Here for instance, is a quick explanation of how to install the linear curve on your D3 (or other Nikon DSLR that uses Picture Controls):

Perhaps not so familiar as you think. The "Linear Tone Curve" is applied on top of the base Picture Control from which it is derived. For example, here is a linear tone curve derived from the Neutral Picture Control:

[attachment=18933:PictureControl.png]

I used this "Linear" curve to photograph the Stouffer wedge and rendered to JPEG in the camera with this setting.
[attachment=18934:ViewNX_SCR.png]

And here is the resulting tone curve as shown by Imatest. It is hardly linear, but is merely the Neutral Picture control with no adjustments.
[attachment=18935:D3_0008_Step_3.png]
« Last Edit: December 27, 2009, 09:29:28 pm by bjanes »
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Tony Beach

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« Reply #26 on: December 27, 2009, 09:57:49 pm »

Quote from: bjanes
Yes, I am familiar with the Picture Control Utility. Thanks for the reference. However, concerning its effect, see below. Fortunately, one does not have to use NX to access the Picture Control Utility (See here).
NX is the term Nikon uses for all of their NEF software, so it can be ViewNX or CaptureNX.

Quote
I'm intimately familiar with the JPEG engine in Nikon's DSLRs, and how that effects the histograms derived therefrom. I'm really not interested in doing a tutorial right now (maybe later), you might want to Google this topic and research it some more. Here for instance, is a quick explanation of how to install the linear curve on your D3 (or other Nikon DSLR that uses Picture Controls)...

Quote
Perhaps not so familiar as you think.
I'm plenty familiar with it.  Enough to know how to install a linear curve, create my own uni-WB, and to set the Picture Controls to accurately reflect the RAW data.  I think it is ironic that for all your examples and arguing, your test shot is underexposed and mine is not.
« Last Edit: December 27, 2009, 09:58:31 pm by Tony Beach »
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bjanes

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« Reply #27 on: December 27, 2009, 10:07:29 pm »

Quote from: Tony Beach
I'm plenty familiar with it.  Enough to know how to install a linear curve, create my own uni-WB, and to set the Picture Controls to accurately reflect the RAW data.  I think it is ironic that for all your examples and arguing, your test shot is underexposed and mine is not.
In my example, I made no attempt to expose fully to the right, but merely was interested in comparing the camera histogram to the raw histogram and used the exposure indicated by matrix metering.

In your example, the Rawnalize histogram demonstrates one stop underexposure and yet you claim to have proper exposure. The raw histogram and the rendered histograms do not match.  

« Last Edit: December 27, 2009, 10:16:39 pm by bjanes »
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Panopeeper

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« Reply #28 on: December 27, 2009, 10:39:58 pm »

Has anyone tried ETTR with a picture style, which contains a custom curve, roughly the inverse of the sRGB mapping (or Adobe RGB, not a big difference from this point), in order to get closer to the raw histograms? I did try that with my Canon 40D and I was not happy about the result, but honestly, I forgot in the meantime why. Of course, the color space conversion can not be disabled. It would be nice to have the option of loading color space conversion matrixes, like in DNG.
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Gabor

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« Reply #29 on: December 28, 2009, 01:49:32 am »

Quote from: bjanes
In your example, the Rawnalize histogram demonstrates one stop underexposure and yet you claim to have proper exposure.



At 1/3 more of a stop some highlights would become unrecoverable, at 2/3 of a stop the colors in the sky, the tree, and the background highlights would shift and become inaccurate.

Quote
The raw histogram and the rendered histograms do not match.
There is no gamma applied to the RAW histogram.
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bjanes

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« Reply #30 on: December 28, 2009, 09:31:16 am »

Quote from: Tony Beach
At 1/3 more of a stop some highlights would become unrecoverable, at 2/3 of a stop the colors in the sky, the tree, and the background highlights would shift and become inaccurate.
What does this Rawnalize screen capture have to do with the previous one where the highlights were 1 stop from clipping?

Quote from: Tony Beach
There is no gamma applied to the RAW histogram.

Of course, the gamma affects the scaling of the X axis as I demonstrated above, but one stop is still one stop. One must take the scaling into account when evaluating histograms. Shown below are two histograms from Photoshop demonstrating a the green channel of Stouffer wedge rendered at gamma 2.2 and gamma 1.0. Unfortunately, the x-axis is not scaled. The patches vary by 0.1 density units, so three of them is about 1 f/stop. In the gamma 2.2, the steps are nearly equal on the right but draw together on the left. With gamma 1.0 (bottom) the steps are expanded on the right and squished together on the left (like the scaling on a slide rule).

[attachment=18941:Iris_Gammas.png]

In my opinion, the best histogram has a log scale as shown below by Guillermo's Histogrammar. A log scale is more perceptually uniform and photographers think in f/stops. The program is free, but if you use it regularly, you should make a donation via Paypal.

[attachment=18942:histogrammar.png]
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Tony Beach

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« Reply #31 on: December 28, 2009, 11:47:13 am »

Quote from: bjanes
What does this Rawnalize screen capture have to do with the previous one where the highlights were 1 stop from clipping?
That screenshot was from the same file as the one used in the previous screenshot, and shows that the highlights are not one stop from clipping, some of them are as little as 1/6 of a stop from clipping, and most of them are within 2/3 of a stop of clipping.

The irony here is that if the shot was exposed a full stop more to the right (which would have disastrous results throughout the image), you would need to set even more negative EC in the RAW converters than what I showed.  This proves my point that if you are not using negative EC for relatively low contrast scenes then you are underexposing them.
« Last Edit: December 28, 2009, 11:51:46 am by Tony Beach »
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bjanes

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« Reply #32 on: December 28, 2009, 12:01:18 pm »

Quote from: Panopeeper
Has anyone tried ETTR with a picture style, which contains a custom curve, roughly the inverse of the sRGB mapping (or Adobe RGB, not a big difference from this point), in order to get closer to the raw histograms? I did try that with my Canon 40D and I was not happy about the result, but honestly, I forgot in the meantime why. Of course, the color space conversion can not be disabled. It would be nice to have the option of loading color space conversion matrixes, like in DNG.

Gabor,

I devised a custom InverseGamma curve using calculated raw pixel values from a Stouffer wedge and using the measured valued in an sRGB rendering.

Calculated values:
[attachment=18949:Excel.gif]

Scatter Plot:
[attachment=18950:InverseGammaExcel.png]

Resulting Picture Control
[attachment=18951:PictureC...rseGamma.png]

Imatest Plot of Inverse Gamma conversion. The results are approximately linear with a gamma of 1. The curve needs more work. The Nikon utility is rather difficult to work with and I need more practice. The exercise disproves Tony Beach's theory of a linear tone curve and demonstrates that the resulting picture control tone curve is on top of the tone curve from which it was derived.
[attachment=18952:D3_0008_Step_3.png]
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Tony Beach

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« Reply #33 on: December 28, 2009, 01:21:41 pm »

Quote from: bjanes
Imatest Plot of Inverse Gamma conversion. The results are approximately linear with a gamma of 1. The curve needs more work. The Nikon utility is rather difficult to work with and I need more practice. The exercise disproves Tony Beach's theory of a linear tone curve and demonstrates that the resulting picture control tone curve is on top of the tone curve from which it was derived.
Totally boring and frankly irrelevant.  The primary issue for the purposes of ETTR is not where the other values appear, but where the highlights are.  Besides that, who cares?  I don't.  Can you show that the non-linearity you are fixated on is caused by the Picture Controls, or that it is actually related to how the sensor captures the data? [Never mind, I don't care about that either.  After all is said and done, we do not create photographs with perfect linearity -- unless all we care about is accurately recording a Stouffer wedge -- so I for one have better things to ponder than this digression from the OP.
« Last Edit: December 28, 2009, 01:23:39 pm by Tony Beach »
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Panopeeper

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« Reply #34 on: December 28, 2009, 04:45:51 pm »

Bill,

regarding non-linearity: Iliah, who knows of Nikon cameras' behavior much more than I do, wrote somewhere, that the raw data requires some channel specific offset to make it linear. You can easily check this in Rawnalyze on the Stouffer wedges: start on a very bright strip, record the intensity values (the AI values, as the distance from clipping in EV), and now go lower and lower by three strips. The decrease in intensity is quote consistent down to the dark strips, but when it gets close to zero, the differences become quite wild, even in 1/3 steps. Unfortunately, I don't know where/how the required offsets are recorded in the NEF MakerNote.
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« Reply #35 on: December 28, 2009, 05:29:10 pm »

Quote from: Panopeeper
Bill,

regarding non-linearity: Iliah, who knows of Nikon cameras' behavior much more than I do, wrote somewhere, that the raw data requires some channel specific offset to make it linear. You can easily check this in Rawnalyze on the Stouffer wedges: start on a very bright strip, record the intensity values (the AI values, as the distance from clipping in EV), and now go lower and lower by three strips. The decrease in intensity is quote consistent down to the dark strips, but when it gets close to zero, the differences become quite wild, even in 1/3 steps. Unfortunately, I don't know where/how the required offsets are recorded in the NEF MakerNote.

Gabor,

I followed your advice and did use Rawnalize to read the raw pixel values of the green channel of the the raw file of a selected image of the step chart and the results are shown. Step one is clipped in the raw file and step 3 is at clipping in the aRGB JPEG. I set the camera to record both raw and JPEG.

[attachment=18959:Excel2.gif]

[attachment=18960:RawVsStep.gif]

[attachment=18962:Raw14_vs_aRGB.gif]

The clipping in the raw is confirmed by Rawnalize:
[attachment=18961:RawnalizeScrCap.png]

I went as far as possible in the shadows until I could no longer see the steps on screen. As you can see, I did not recover the shadow portion of the S curve.

I constructed an inverse gamma curve in the Picture Control utility with slightly better results than before. Since the JPEG is at clipping in step 3 and the Picture Control curve appears to be applied on top of the base picture control, I can devise no method to show step 2 of the wedge at 255, because the data are already clipped. Any suggestions?
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Panopeeper

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« Reply #36 on: December 29, 2009, 12:50:59 am »

Quote from: bjanes
I followed your advice and did use Rawnalize to read the raw pixel values of the green channel of the the raw file of a selected image of the step chart and the results are shown
What is the Raw_255 value in the chart?

Quote
I went as far as possible in the shadows until I could no longer see the steps on screen. As you can see, I did not recover the shadow portion of the S curve
Why don't you increase the intensity (add 3-4 EV)? The raw clipping shows, how far it is reasonable to go: when there are many clipped pixels, the result can not (or should not) be in line with the other strips, because the reduction between such steps is less than 1/3 EV.

Quote
Since the JPEG is at clipping in step 3 and the Picture Control curve appears to be applied on top of the base picture control, I can devise no method to show step 2 of the wedge at 255, because the data are already clipped. Any suggestions?
Simply reducing the intensity by negative "exposure" adjustment of ACR?
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« Reply #37 on: December 29, 2009, 08:41:26 am »

Quote from: Panopeeper
What is the Raw_255 value in the chart

Raw_255 is merely the raw value expressed in 8 bit (0..255) notation. Raw_255 = Raw value/16383 * 255.
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bjanes

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« Reply #38 on: December 30, 2009, 03:09:57 pm »

Quote from: Tony Beach
The irony here is that if the shot was exposed a full stop more to the right (which would have disastrous results throughout the image), you would need to set even more negative EC in the RAW converters than what I showed.  This proves my point that if you are not using negative EC for relatively low contrast scenes then you are underexposing them.
That is often the case, but whether or not negative exposure is required for proper ETTR exposure of short scale subjects depends on the distribution of tones within the subject. For the purpose of demonstration, I will use a Kodak Q14 chart. With a full scale image, exposing for mid tones gives proper exposure with the highlights just short of clipping. No negative exposure correction is needed; the -0.5 EV in ACR is to correct for the BaselineExposure offset that ACR uses for this camera.

[attachment=19029:FullScale.png]

With a short scale subject centered on the midtones and using normal exposure,  there would be room on either end of the histogram. Optimum ETTR exposure would require an increase of exposure to place the highlights just short of clipping; one would then have to use negative exposure compensation in the raw converter to bring the tones down to where they should be.

[attachment=19031:MidKey.png]

With a high key image proper ETTR exposure would again place the highlights just short of clipping.  However, in this case no negative exposure compensation would be necessary since the highlights are already where they should be.

[attachment=19033:HighKey.png]
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Tony Beach

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« Reply #39 on: December 30, 2009, 06:23:12 pm »

Quote from: bjanes
That is often the case,
In the example I offered it was the case.  I was already over a stop past what the meter was indicating as a "proper" exposure for that scene.  That was for Center-weighted metering; and while it may well have been closer using Matrix metering, I don't really care because I simply avoid Matrix metering for several reasons.  What is scary about this is that if a photographer relies on Nikon's metering and then goes to pull the shadow detail up, they will bring up an extra stop of noise and hit the practical limits of the sensor's DR that much sooner.

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but whether or not negative exposure is required for proper ETTR exposure of short scale subjects depends on the distribution of tones within the subject. For the purpose of demonstration, I will use a Kodak Q14 chart. With a full scale image, exposing for mid tones gives proper exposure with the highlights just short of clipping. No negative exposure correction is needed; the -0.5 EV in ACR is to correct for the BaselineExposure offset that ACR uses for this camera.
I still don't get your "BaselineExposure offset" argument, since you are essentially saying that you are applying negative EC to ACR's default -- this strikes me as being a semantical disagreement.  Also (as I already said), there are other RAW converters, and the use of negative EC is close to universal to all of them for RAW conversions of ETTR files (again, assuming a lower contrast scene).  Of course for high key photographs you will probably skip negative EC in RAW conversion.

For higher contrast scenes it is a struggle to simply keep the highlights from blowing while retaining shadow detail -- so the histogram will stretch from one end to the other even starting with ETTR.  Often metering for those scenes requires no adjustment or even negative adjustment, and how you deal with it depends on whether loosing highlight detail and color accuracy is more or less important than noise in the subject (depending of course on how many stops down from the highlights that subject is).
« Last Edit: December 30, 2009, 06:24:13 pm by Tony Beach »
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