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Jeff Schewe wrote:
TK2142 wrote:
In thread , Eric acknowledges that the above two things have "
Uh huh...did you actually read what he wrote? "Dorin, the automatic aspect has to do with the endpoint (i.e., white point & black point) handling. The shape of the curve is calculated automatically to make transitions smoother as you approach clipping (to pure white or pure black). Otherwise you'd get the traditional digital "hard clip" which can be rather rough, esp. in the shadows."
So, I ask again, do you understand what Eric is talking about? That the highlights and shadows aren't being automatically being set but the RANGE is? The "image adaptive" aspect is setting the end points for highlights and shadows? So that the range of the PV 2012 adjustments are image dependent?
Again, that's considerably different that saying highlights and shadows are being set "Automatically".
TK2142 wrote:
Please do not accuse someone of not knowing what is going on when you are not sure.
Well, I seem to be just a bit more sure of what's going on than you are...correct me if I'm wrong.
The "image adaptive" adjustments that ACR7/LR4 performs are not clear to me (and apparently others). Certainly, the technical paper on LaPlacian operators is incomprehensible to me and likely most other readers of this thread. Rather than attempting to parse Eric's statements, a bit of empirical observation can shed some light on the matter.
A Stouffer wedge is a good way to evaluate the tone curve, since each step is 0.1 OD or approximately 3 steps per f/stop. Here is the wedge exposed so that step 1 is just short of clipping in the green channel and rendered into sRGB with ACR 6.6 with a linear tone curve (sliders 0 on the main tab and point curve set to linear). The image is approximately scene referred and approximates how the wedge appeared to the eye.
Step one has an OD of 0.05, but I placed it at a pixel value of 255. Steps 8 and 9 are near mid-gray (18%). Calculated values are shown in this Excel spreadsheet. The values A, M and B correspond to the steps on a Kodak Q14 chart which represents the values in many real scenes for highlight, midtone, and shadows.
Here is the ACR 7.0 PV2010 preview with the rendered sRGB values. An exposure of -0.5 EV was necessary to allow for the BaselineOffset that PV2010 uses.
And here is the PV2012 view with default settings. The highlights are too bright and scrunched together.
And here are the settings needed with PV2012 to approximate the linear curve in PV2010. I had to invoke the point curve to place the midtones as I could not get the proper values for the mid-tones with the sliders.
And now to the subject of automatic highlight recovery. It is necessary to use a special program to reveal the true status of the raw file, and I used Rawdigger. The histograms of the normally exposed image (05) and an image overexposed by 2/3 stop (image 03) are shown. In the overexposed shot the green channels are clipped and the red and blue channels are short of clipping, enabling highlight recovery.
And finally, here is the overexposed image (03) with the default PV2012 settings. It is clear that automatic highlight recovery has been performed as step 1 is now at a pixel value of 254 (I used an exposure of -0.05 EV to show that the pixel value was likely not clipped to 255). This is OK with me, but it does mean that proper ETTR exposure is diffucult to judge with PV2012 because of the automatic recovery. I anticipate that some readers will reply that they take photos of real scenes and not stepwedges and that scene referred images appear flat.
Personally, I am quite pleased with the changes in PV2012 for processing of real world images, but one does need to learn how to best use the new tools.
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Mess? Let's talk about a mess.
I tried PV 2010 zeroed, and that is a massive mess. It's like the ultimate "make my image look like crap" button - horrible skin tones, nasty colors on everything. The only way that would be usable is if I also created a custom color profile designed for that tone curve. The first thing I did was use the controls to undo most of what it did.
The profiles and the tone curves are designed to work togethger to produce a "pleasing", rather than scientifically accurate image. The second is really only usable for science (spectroscopy, for example).
This is all a major tempest in a teapot in my opinion. PV2010 zeroed on the top, PV2012 defaults on the bottom.
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404 posts
Jan 20, 2010Michael Frye's second video on the PV 2012 controls is out.
(Partial) Summary:
- There is no ideal starting point that fits all images.
- For some images (including your's, Lee Jay), the Adobe default is a better starting point than completely flat settings.
- But often the Adobe defaults (brightness boost) compress highlight contrast and lead to a "washed out" look.
- Hence many images benefit from getting tweaked from more neutral settings (i.e., without the default brightness and contrast boosts).
- It is easier (in terms of getting to where you want to be with an image) to add contrast to an image (at the working points and with the levels it needs) then to remove contrast.
- The PV 2012 basic panel controls are better than the PV 2010 controls in the sense that they more easily allow to mimic changes you would do to the tone curve.
- But the tone curve still allows more precise control (partially because you can fine tweak the working points of your boost points).
- The tradition of setting white and black points first still makes sense. One should therefore question the suggestion to use the basic panel control sliders in the order they present themselves. Often it is better to first set "Whites" and "Blacks" and then go to "Exposure". Eric Chan argued differently in a post, referring to the fact that tweaking "Exposure" will affect the whites and thus invalidate adjustments to "Whites" but surely this argument goes both ways, as the overlap is symmetric. If you tweak "Exposure" first, you'll have to revisit its setting again if you subsequently tweak "Whites". Revisiting hence seems inevitable but makes more sense to me to get the whitepoint right before you start compressing contrast with the "Exposure" slider against a whitepoint that is too low.
The video contains some further images which demonstrate the above points. To me all this reinforces that it was a baid idea to choose "0" to mean an arbitrary Adobe default whose built-in contrast and brightness boosts are not suited for certain images.
If you can learn something from the video, great!
If you still disagree with me, you don't have to tell me again.
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TK2142 wrote:
If you still disagree with me, you don't have to tell me again.
The only point I would still argue is that there's a reason Eric said what he said...if you don't first set the overall tone in Exposure then you're working on an image whose overall tone is wrong. Exposure and Contrast first does set up Highlights and Shadows nicely making Whites and Blacks being relegated to fine tuning (or jumping to Curves).
Note, I don't think Curves use (point or parametric) has been eliminated, but I think the need to go to curves has been reduced...
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Hi TK,
I don't have much of an opinion about the '0' points.
But have you created the lowered contrast DNG profile yet?
That's a good solution for the "linear" tone curve being contrastier in PV2012.
In fact, it's a good solution for anytime you want a different tonal starting point, since that way you don't have to start with a bunch of points already on the curve.
But note: the tone curve in the profile does not provide the input to the basic sliders - they operate on the raw data the same way regardless of the tone curve in the profile. It's more like it sits between the basic sliders and the tone curve control in Lightroom, so to speak (or maybe "under" the Lightroom tone curve...). Anyway, one can not use a DNG profile to alter the behavior of the basic sliders, only to get a head start on tonal adjustment via the Lightroom curves, or obviate the need for it...
Regarding blacks & whites:
----------------------------------
- Not always a good idea to do them first, but not always a good idea to leave them till last either. The sliders in PV2012 are like a team - I rarely adjust one without adjusting one or more (or all) the others too, up until the last adjustment I mean
. Like all other PV2012 sliders, blacks & whites sometimes only need small tweaks (or none), but sometimes they need big ones. They are really not the same as setting black/white point as in days of old...The original conception and intent may have been for fine-tuning, but that does not always pan out in practice, - not for me.
PV2012 rocks! 
(except when it doesn't 
).Cheers,
Rob
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Jeff Schewe wrote:
TK2142 wrote:
If you still disagree with me, you don't have to tell me again.
The only point I would still argue is that there's a reason Eric said what he said...if you don't first set the overall tone in Exposure then you're working on an image whose overall tone is wrong. Exposure and Contrast first does set up Highlights and Shadows nicely making Whites and Blacks being relegated to fine tuning (or jumping to Curves).
Note, I don't think Curves use (point or parametric) has been eliminated, but I think the need to go to curves has been reduced...
I agree that it makes sense get exposure right before proceeding to other corrections, but the behavior of exposure is different in PV2012 from PV2010. In PV2012 the black and white points are automatically set (within limits), and my current understanding is that one would use exposure to set the midtones. In PV2012, the exposure slider targets the midtones as shown on the LR histogram, but it is essentially a linear operator if recovery is not being performed and it also affects the highlilghts. One could then direct attention to the highlights to extract maximum tonality.
In your previous LuLa ACR tutorial Thomas Knoll reported that when editing images (that would be with PV2010), he first sets the white point with exposure. The midtones might then need a correction with brightness. He stated that an alternate method would be to set the midtones with exposure, and then the white point with recovery. This alternate method appears to be needed in PV2012 since there is no brightness slider. The highlight slider does affect the midtones to some extent, but it operates mainly in the highlight region as its name indicates. Your comments would be welcome.
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404 posts
Jan 20, 2010Lee Jay wrote:
Adjust exposure, then fiddle with +shadows and -highlights until things are about right. If the exposure was set correctly, the two numbers will be the same but opposite in sign. If they aren't, adjust exposure.
Interesting that you should use the term "fiddle".
In any event, you do not seem to have images that require more sophisticated adjustments. If your approach worked for everything then Adobe should have provided just one "shadows/highligts" slider to be adjusted in conjunction with "exposure". It does not make sense to allow different values for "shadows" and "highlights" when the best setting always requires them to have the same value anyhow.
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TK2142 wrote:
Lee Jay wrote:
Adjust exposure, then fiddle with +shadows and -highlights until things are about right. If the exposure was set correctly, the two numbers will be the same but opposite in sign. If they aren't, adjust exposure.
Interesting that you should use the term "fiddle".
In any event, you do not seem to have images that require more sophisticated adjustments. If your approach worked for everything then Adobe should have provided just one "shadows/highligts" slider to be adjusted in conjunction with "exposure". It does not make sense to allow different values for "shadows" and "highlights" when the best setting always requires them to have the same value anyhow.
I do, but they are rare. A good 90+% of my images can be satisfactorily adjusted using this basic approach. Every once in a while I have a pathological case that needs more fiddling.
I'm not going for "effect", I'm going for "realistic". PS is the effects tool.
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