Metering tonality...18% or 12%?

I was alluding to the method espoused earlier, of metering a highlight target (white towel) and backing off -3EV, for example.

In any event, one thing that has been forgotten (or ignored) is that the entire dynamic range of a scene might well surpass the ability of the digital sensor (or film) to capture it, and then the idea of 'get rid of the blinkies' or 'back off to get the pixels on the histogram' can be a foolish way to cope with the scene.

Wilt wrote in post #12139746
I was alluding to the method espoused earlier, of metering a highlight target (white towel) and backing off -3EV, for example.

In any event, one thing that has been forgotten (or ignored) is that the entire dynamic range of a scene might well surpass the ability of the digital sensor (or film) to capture it, and then the idea of 'get rid of the blinkies' or 'back off to get the pixels on the histogram' can be a foolish way to cope with the scene.

Heh! So...I assume there that you are referring to being able to "write off" unnecessary highlights?

tonylong wrote in post #12139857
Heh! So...I assume there that you are referring to being able to "write off" unnecessary highlights?

Yes, indeed! It is up to the photographer to make a judgement about what portions need to be kept, and which are eliminated. Much like the example posted by tdodd in post 64.

Sure, I agree -- I avoid the blinkies when I want everything in the scene to be unclipped But yeah, there are times you just have to let some things go...'course being careful that only the unneeded ones are clipping.

tdodd wrote in post #12138698
Yes, your clipping point is what counts, regardless of which camera. So get to know your camera(s) and where its/their limits lie.

Even if cameras come along with extended dynamic range I can't see much sense in driving the mid tones further down into the shadows and noise. You'd still want to keep your exposure shifted to the right to maximise photon capture. What use is 4 stops of highlight headroom if you keep not using the top stop or more? All exposures should be relative to full well saturation, not some arbitrary mid tone value that in itself has no meaning. Clipping point defines the limits. IMHO.

This is why the technique you described made so much sense to me when I read it.

tzalman,
Thanks for reminding me about UFRaw. I use GIMP, so I'm going to install it and try that out. Hopefully that will enable me to go totally GIMP rather than having to use DPP to create a jgp and then using GIMP (when it supports the 60D!).

Wow, I've just installed the latest version of GIMP, 2.6.11 for Windows, with the Help install, and then finally UFRaw. I didn't expect it to work with my 60D RAW files, but it does.
I have no idea what all this means, but is certainly looks interesting:

OK, I've only got DPP to compare with. UFRaw seems to have a lot more in it. I can just drag a CR2 file into GIMP and UFRaw just opens. Then when I'm done, I can click a button and GIMP opens with the image with no intermediate file needing to be saved.

Here's a quick list of what I've found:

============

Exposure compensation +/-6 EV - DPP only has +/-2 EV.
Exposure options: Restore details for negative EV, Clip highlights for positive EV, Auto adjust - not sure how well these work or quite what they do.

White balance:
- Camera WB displays temperature used - I've not found how to do that in DPP.
- It shows channel multipliers - I think this could be handy too.
- Denoise - I'll probably leave this at 0 and do the noise/sharpening in GIMP.

Greyscale mode
Lens Correction

Base Curve:
- Linear curve & Manual curve (curves tool)
- Colour Management
- Gamma
- Linearity
- Output intent
- Display intent

Current luminosity and Saturation
- Auto adjust black and white points

Lightness adjustment

Crop and rotate

Send image to GIMP

==============

I suspect I'm not going to be using DPP much more.

Steve -
You have made me nostalgic for UFRaw! It is an excellent application, as are so many Open Source programs which are the products of amazing devotion, generousity and creativity. What I particularly love is the transparency, both in forums and in the UI. Showing the temperature and the multipliers is an example. IIRC, there is an option for showing the top histogram without the conversion curves, the real pre-conversion data. And again IIRC, the N.R. is Dave Coffin's wavelet N.R. which is done on the linear data and is excellent (and I suspect is the inspiration for LR/ACR's new N.R.) so I'd give it a test drive.

My method is to use spot metering. I first evaluate the scene I am about to shoot by passing the spot meter over various parts of the scene. Adjusting my exposure. I check for blown highlights and lost shadow detail. But in the end I will always settle for an exposure setting that will expose my main subject. I let the rest lay where it falls. Once I get home I try to "fix" some of these areas. But I try to keep the picture looking real. Not ever scene can be exposed to fit within the sensors dynamic range. And then you can throw in all that artistic licensing thing and do what ever the heck you want.

AbPho wrote in post #12143728
My method is to use spot metering. I first evaluate the scene I am about to shoot by passing the spot meter over various parts of the scene. Adjusting my exposure. I check for blown highlights and lost shadow detail. But in the end I will always settle for an exposure setting that will expose my main subject. I let the rest lay where it falls. Once I get home I try to "fix" some of these areas. But I try to keep the picture looking real. Not ever scene can be exposed to fit within the sensors dynamic range. And then you can throw in all that artistic licensing thing and do what ever the heck you want.

^^^ ...what I do, too.
It would seem that you understand quite well the Zone System exposure evaluation technique, and how to make the value judgement -- from shot to shot (or subject to subject) -- of what is most important to preserve in the shot, and to expose accordingly!

Many pros employ this technique for commercial photography, all the time when the intended media is created by the offset press, since that is not able to reproduce the dynamic range of what can be captured even by color transparency or digital.

No print on paper can, so it's always a consideration for anyone making a print: Not only can the film or sensor not cover a scene of wide dynamic range, but silver halide, dyes, or pigments on paper can't even cover the dynamic range of a piece of film or an image on a monitor.

RDKirk wrote in post #12143856
No print on paper can, so it's always a consideration for anyone making a print: Not only can the film or sensor not cover a scene of wide dynamic range, but silver halide, dyes, or pigments on paper can't even cover the dynamic range of a piece of film or an image on a monitor.

^
Taken from http://www.scantips.co​m/basics14.html, which is more about scanning, but contains pertinent information about comparative dynamic range content...

"A printed magazine image has a dynamic range well less than 2.0, maybe half of that (1.7). The blackest ink still reflects some light, the white paper is not so bright that it blinds us, and the difference is relatively small. Photographic color prints have a dynamic range of less than 2.0 too. Film negatives might have a range up near 2.8. Slides may be near 3.2. These are not precise numbers. "

At the same time there are articles such as this, http://www.studentphot​o.com/files/members/Pa​sley0799.pdf
which state,

"A properly exposed transparency can display a tonal range of almost 8 f/stops, from the
brightest highlight to the darkest shadow. While the image may look sharp and detailed on a light
box, it poses a problem for the printing press, which has a tonal range
equivalent to only 4 f/stops...
The answer was discovered in 1986 by Hans Carl Koch and Gerhard
Muhlebach of Sinar Bron A.G. They found that if you limit the tonal range
of the transparency to match the tonal range of the printing press, the quality
of the image reproduced on the printed page will be much better. This is accomplished
by measuring the light striking the camera’s film plane and adjusting
the studio lighting so that the tonal range is only 4 f/stops from the brightest
highlight to the darkest shadow."


At the same time, articles such as this http://www.normankoren​.com/digital_tonality.​html
disclose, "a print can only reproduce a tonal range of about 100:1-- 6.6 f-stops"


In other words, the dynamic range of lighting in the scene is an additional variable, over and above the issue of the dynamic range of the media upon which it is presented. And that is the reason for spotmetering highlight vs. shadow area, as descriribed by AbPho.

I love threads like this.

It just brings out so much information, whether we us it or not.

Wilt wrote in post #12144135
^
Taken from http://www.scantips.co​m/basics14.html, which is more about scanning, but contains pertinent information about comparative dynamic range content...

"A printed magazine image has a dynamic range well less than 2.0, maybe half of that (1.7). The blackest ink still reflects some light, the white paper is not so bright that it blinds us, and the difference is relatively small. Photographic color prints have a dynamic range of less than 2.0 too. Film negatives might have a range up near 2.8. Slides may be near 3.2. These are not precise numbers. "

I happen to be the author of scantips.com, and perhaps you missed the point, that density ratios and intensity ratios are different numbers. Page two there has more explanation. The numbers are from Kodak, as credited. Kodak says the "DMax limit of best transparency" is 3.2.

Density steps (like your gray scale wedges) change in steps 0.3 density for every 2x intensity change (same way that ND filters are named).

Log 10 (2) = 0.3 density change = 1 stop = 2x intensity.

Printed material works according to density. This is the definition of density.

For example... 12 bit data. Minimum and Maximum numbers it can contain are 0 and 4095. That is the largest range that can possibly exist (it doe NOT imply our data reaches that capability, this is merely the size of the container).

Log 10 (4095) is 3.6... subtract 0, and ideally the density range is 3.6. The maximum density difference which can exist. Real world sometimes falls a little short, but it will not be more. 8 bits is 2.4 maximum.

DMin is not zero. However, any 12 bit scanner specification will always automatically say 3.6 without any qualification. None can actually ever do it, nor does the media have that range either. It is NEVER a rating of what the scanner can and does do.

WayneF wrote in post #12145087
I happen to be the author of scantips.com, and perhaps you missed the point, that density ratios and intensity ratios are different numbers. Page two there has more explanation. The numbers are from Kodak, as credited. Kodak says the "DMax limit of best transparency" is 3.2.

Density steps (like your gray scale wedges) change in steps 0.3 density for every 2x intensity change (same way that ND filters are named).

Log 10 (2) = 0.3 density change = 1 stop = 2x intensity.

Printed material works according to density.

For example... 12 bit data. Minimum and Maximum numbers it can contain are 0 and 4095. That is the largest range that can possibly exist (it doe NOT imply our data reaches that capability, this is merely the size of the container).

Log 10 (4095) is 3.6... subtract 0, and ideally the density range is 3.6. The maximum density difference which can exist. Real world sometimes falls a little short, but it will not be more. 8 bits is 2.4 maximum.

Wayne, no I understood.

It was Skip who mentioned prints and offset printing similarity -- density ratio. I then also referred to the density ratio of negatives and transparencies.

I then pointed out the intensity ratios of lighting contrast reproducible with offset printing vs. photographically.