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5 Days Ago   #46
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QuoteOriginally posted by normhead Quote
Contrast has more effect on the perception of detail than straight colour depth.

.

Already addressed. Having 1000 shades of grey instead of 20,000 makes no difference to the final image. They are both far more than you can see. You can't get it back, but, cameras are designed as they are, because you don't need it. So, no ridiculously over sampled colour depth is not part of detail. You can't tell the difference in most cases between 16 black values and 256 black values. And no colour depth isn't that important in detail. Contrast and micro contrast and lens resolution are much more important.

You seriously need to try some photos to test these things out. Those of us who regularly bracket deal with this issue day in day out. It's pointless having a theoretical discussion about it. Honestly, take a nice bright scene and bracket, then examine what you get with the various exposure settings. What I'm discussing will become immediately apparent. It's not rocket science. And with digital, bracketing is cheap.
Surely micro-contrast is going to be aided by exposing to the right as it will allow more shades to be recorded.


Last edited by mccririck; 5 Days Ago at 01:01 PM.
5 Days Ago   #47
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QuoteOriginally posted by mccririck Quote
Surely micro-contrast is going to be aided by exposing to the right as it will allow more shades to be recorded.
Often the opposite is the case.
It all depends on being meaningful to the output device. To little isn't good, too much isn't good.

This K20D image with less dynamic range still has great contrast. (11.1 EV).


This high EV K-1 image looks almost pastel by comparison. (14.9 EV)


You have to remember, no matter what you start with in EV, you're going to be squeezing it into an 8 bit (8 EV, 256:1 contrast) output device. With the K-1 I often end up squeezing most of the image into 90% of the frame, basically ignoring the high end and low end, because I want to accurately display the mid tones, and I can't do that using all 14 EV. So there is more difference in appearance between the different gradations. I have 14 EV, but Im only using maybe 10, to keep my contrast looking natural.

Because those 10 translate to a more natural looking image the using all 14 EV would. Micro contrast, in my experience is more a function of lens quality than colour depth. The CA values of a lens at given focal length can do much more to kill micro-contrast then colour depth. As long as you don't get banding, less colour depth can increase apparent contrast.

I once did a comparison of the same scene with the DA*60-250, Tamron 90, and Sigma 70-300 all at 90mm. The way you could tell the difference was the micro-contrast. IN every other metric they were identical. The Tamron 90 and DA*60-250 were near identical with the Tamron having slight edge. The Sigma was equally as good in every aspect but micro-contrast. As far as I can tell, if your lens can produce it, you camera will capture it. Even 10 year old cameras like my K20D.

Last edited by normhead; 5 Days Ago at 01:48 PM.
5 Days Ago   #48
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QuoteOriginally posted by normhead Quote
This K20D image with less dynamic range still has great contrast. (11.1 EV).
My understanding is that more sensor dynamic range leads to less contrast (contrast to be added in post), and less sensor dynamic range give more contrast out of the sensor.

---------- Post added 12-07-19 at 22:49 ----------

QuoteOriginally posted by mccririck Quote
Surely micro-contrast is going to be aided by exposing to the right as it will allow more shades to be recorded.
You could photograph clouds before a storm, with the intention to show all the micro-contrast of the clouds from grey to pure white, and to do so you have to expose to the left (ETTL). If you expose to the right you'll lose all micro-contrast in the clouds.

Last edited by biz-engineer; 5 Days Ago at 02:01 PM.
5 Days Ago   #49
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QuoteOriginally posted by biz-engineer Quote
In theory you are right, assuming your image has a constant histogram. In practice, if you image contains a lot of dark (e.g foreground grass) and a lot of bright (white cloud) with nothing in the middle (U shaped histogram), exposing to the right will give you a lot of tone definition for the whiteness of the cloud and a poor tone definition for the foreground. That is precisely why on raw processing tool you have high light recover tool, to allow to obliterate the pure white in order to have more tone definition in the shadows.
Well it's hard to expose to the right in such a situation! You really need to choose which is more important to you - the highlights or the shadows. And if it's the shadows you might choose to blow the sky to make the most of your subject.

5 Days Ago   #50
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QuoteOriginally posted by mccririck Quote
Well it's hard to expose to the right in such a situation! You really need to choose which is more important to you - the highlights or the shadows
yes, exactly.
5 Days Ago - 1 Like   #51
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QuoteOriginally posted by mccririck Quote
Well it's hard to expose to the right in such a situation! You really need to choose which is more important to you - the highlights or the shadows. And if it's the shadows you might choose to blow the sky to make the most of your subject.
I would call that ETTS (Expose To The Subject).


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4 Days Ago   #52
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QuoteOriginally posted by normhead Quote
You aren't even talking about what I was talking about. I was discussing colour depth, not Dynamic range, I think you must have read it too quickly. But with regards to that, bringing dynamic range and noise into the equation obscures the issue. You avoid loss of DR by shooting 100 or 200 ISO. That has nothing to do with either colour depth or ETTR.
Good grief! How can you say that? What definition of color depth are you using?

The one that I know about (Color depth - DxOMark) has a direct linkage between color depth and DR that is defined by the color attenuation and separation characteristics of the Bayer filters*. In the case of the K-1 there is an extremely linear relationship between DR and color depth with each bit of DR providing about 1.5 bits of color depth. Color depth is effectively the color version of DR.

ETTR naturally recommends shooting at base ISO because ETTR is all about maximizing DR (and color depth) in order to resolve as much detail as possible by avoiding as much image noise as possible. And whether you measure noise and resolution in B&W or color doesn't really change anything because they are so directly linked by the spectra of the Bayer color filters.

*Another definition of color depth used in computers and display systems (Color depth - Wikipedia) only considers the set of possible digital values of the digital data. By this second definition, both the K-1 and the K-3 RAW files have a color depth of 42-bits (14 bits each in RGB) at all ISO levels.
4 Days Ago   #53
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My hand is directly linked to my arm, but it's not the same as my arm.

Using the definition of DR as the ratio between the lowest amount of light captured, what kind of link can that be? With all due respect, that doesn't make sense to me. You can have great DR with little to no colour depth. 2 bit colour can have as much DR as 14 bit colour. All that has to happen is that the white (11) that is captured is 15 EV brighter than the black (00).

But even if it's true, is there enough difference between 12 bit raw and 14 bit raw to be of any importance?

I've investigated this, and found no discernible practical difference between my 14 bit K20D and my 12 bit K-x.

I've posted examples, and explained why I think the way I do.

Please take some example shots and show me why you think ETTR is better, or demonstrate that more colour depth leads to more DR?

What I'm getting back is theoretical, and what I consider to be questionable DxO analysis in which they co-opt common photographic terms and misrepresent them.

To me this is focussing on little bits of technical trivia of no practical use. As with most things DxO, you know what they said, but what they said is disputable and controversial. And as far as I can tell of no practical value to photographers.

Please show me why the way you think is more appropriate, with images? After all, it really doesn't matter if there's a difference between cameras powered by hamsters on wheels and cameras that use mice, if it makes no difference to my images


Last edited by BigMackCam; 4 Days Ago at 12:45 PM. Reason: A little less animation required
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