Luminous Landscape Forum
Raw & Post Processing, Printing => Digital Image Processing => Topic started by: JimAscher on December 24, 2010, 01:31:54 pm
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When I switched earlier this year (2010) from film and darkroom photography to digital photography, in addition to giving away all my darkroom equipment, I also gave away my full collection of the late Fred Picker's Zone VI newsletters and instructional videos. So what I'm about to summarize is based entirely on memory.
Fred's modification of Ansel Adams' Zone metering concepts was based on something of a simplification, but I thought very pertinent and effective. Rather than trying to establish certain zone values for a scene, you should instead strive merely(!) to capture what Fred termed (as I recall it) the "Maximum Printable Negative.' That is (obviously) to produce a negative with as full a range of light values from a chosen scene that the limitations of your film would permit. In Fred's view, as I understood it, you don't need to strive to have your negative represent your final aesthetic intent, but rather have the negative contain the maximum information possible to achieve that aesthetic intent in the DARKROOM.
Now, as I see it, the corollary to this for a digital photographer and processor is to similarly achieve a digital capture in the RAW form of a "maximum printable negative.' Then, through a RAW exposure adjustment (and any other adjustment) in the processing software, the photographer's aesthetic intent can better be realized. For most of forum members reading this, the most logical comment will be "Duh!" It IS rather obvious. So, I guess what I'm saying is that, for those photographers (other than point-and-shooters), who employ post-processing software, establish with your camera the broadest range of exposure you can and deal with aesthetic tonality later, in the comfort of your PC.
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In digital terms, use base ISO, or don´t go above an ISO where you start loosing DR, and ETTR (without blowing any channel)
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Yes,
That's it! Perfect!
Best Regards
Erik
In digital terms, use base ISO, or don´t go above an ISO where you start loosing DR, and ETTR (without blowing any channel)
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In digital terms, use base ISO, or don´t go above an ISO where you start loosing DR, and ETTR (without blowing any channel)
Francisco (and Erik): In its succinctness your response is like the tip of an iceberg. The volume under the surface is massive, and hides from view the wealth of discussion (controversy) regarding ETTR over recent years (including in this forum). On its face (switching metaphors) your response does provide the possible means to a digital equivalent of Picker's "Maximum Printable Negative." It might be regarded by some as verging on the trite, glib and truistic (although I, for one, would not employ those terms), if not for the fact of your inserted qualifiers which would seem to counter most of the ETTR opposition. Those qualifiers being the need to start with a base ISO, not losing DR and not blowing any channel through use of ETTR. Who can really argue or find fault with that? So, in my view, on balance, your response is a quite respectable answer -- but is it a valid solution?
With my admittedly limited technical understanding of all the objections that have been posted to the actual efficacy of ETTR, my pragmatic concern is regarding the inability within most digital cameras of attaining a viable histogram of the RAW image to enable ETTR to be successfully employed. I have seen in related internet postings on this subject the diverse efforts and suggestions for various in-camera adjustments to make the histogram sufficiently "resemble" the RAW image as to make ETTR work. It's possibly something like the convolutions the medieval church logicians went through to provide a demonstration of how the sun went around the earth, or that planets had circular orbits.
The question, and concern, for me therefore remains -- without a valid in-camera histogram of the RAW image, can the employment of ETTR be any more than only marginally effective, and really any usefully better than the camera's native exposure determining mechanism?
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discussion (controversy) regarding ETTR over recent years (including in this forum).
There is really no controversy, just misunderstanding...
If the scene contrast range is within the dynamic range of the sensor, you can reduce noise (and improve signal to noise ratio) in the shadows by ETTR. That is fact...not myth.
The "controversy" is born out of a lack of understanding of scene contrast, sensor dynamic range and how to meter for digital. Full sun-lite scenes are not really candidates for ETTR...overcast low-contrast scenes are.
It all depends on the scene...and what you want to get from it.
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There is really no controversy, just misunderstanding...
If the scene contrast range is within the dynamic range of the sensor, you can reduce noise (and improve signal to noise ratio) in the shadows by ETTR. That is fact...not myth.
The "controversy" is born out of a lack of understanding of scene contrast, sensor dynamic range and how to meter for digital. Full sun-lite scenes are not really candidates for ETTR...overcast low-contrast scenes are.
It all depends on the scene...and what you want to get from it.
Yep, back to Fred Picker. "(S)ensor dynamic range and how to meter for digital" is the direct equivalent of Fred's concern for the (limited) dynamic range of film and how best to meter for it. If we cannot really trust the digital camera's metering and histogram depiction, one option is to go back to using an external exposure meter and manually increasing the exposure three f-stops from the metered gray (if I remember Fred's methodology correctly).
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Metering for film and digital are different. The first question is what is the scene contrast range? Is it less than the dynamic range of the sensor? If not, ETTR is not relevant. If the scene is less than the contrast range of the sensor then you do want ETTR unless you want to leave IQ on the table. How much ETTR? Depends on the scene...and yes, I suppose you COULD use an external meter...I would suggest a spot meter so you could meter the scene and determine the contrast range. Otherwise, doing a reflected meter reading and opening up 3 stops (which completely depends on your meter) would be less optimal that using your camera.
You seem hellbent on making this stuff a lot more difficult than it is. And you CAN tell a lot from the histogram on the LCD...you just can't see the entire raw histogram.
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Jim, I'm familiar with Picker's book and still have the Zone VI workshop in my bookcase. I also had the newsletters which were occasionally valuable. I think Ansel Adams book on the negative was more valuable from my perspective than Picker's book. The zone system works for film because of the properties of film with respect to light. Jeff is correct that digital is different and you can't assume that what you did for film will translate equally. Last spring when the big DR debate was going on here I did my own experiment. I taped Jack Flesher's test print and my X-Rite passport to a piece of white matte board and did a whole series of test exposures. It was done outside on a cloudless day so the illumination was constant. No direct sunlight fell on the test board. What this did allow me to do was correlate readings from the in camera meter (Nikon D300) and relate this to the histogram on the camera so that I could tell how good/bad it was. Once the images were downloaded to Lightroom, you can look at the RAW histogram and compare these to the in camera histogram (as long as you didn't reformat the memory card!). I found that there was a darn good correlation. In addition I also had a series of exposures that allowed me to gauge the optimum ETTR (and ETTL :D) that gives me the type of information needed to get the right exposure in the field. Jeff is correct that a lot of it depends on the subject matter and light. That being said, it's more straight forward than application of the Zone system with film.
Alan
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That being said, it's more straight forward than application of the Zone system with film.
What some people forget is that AA's Zone System depended upon not only metering and exposing the film, but also processing of the film to adjust the tone curve before printing on various paper contrasts. Changing the contrast of the file in development was far more difficult than dealing with post-processing in digital. There is no comparison...to try to convert any sort of zone system (notice the lowercase z) from film to digital is to ignore and misunderstand digital's fundamental difference...raw captures are essentially linear. That means the brightest stop of exposure in a digital capture contains 1/2 of ALL the levels the capture can contain. That is a fundamental disconnect from film...
You would be far better off to discard what you think you know and learn what you need to know regarding digital. Digital ain't film...and trying to apply film-based experience will lead you down the wrong path. Seriously...been there, got the tee-shirt, I don't need/want the scars!
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Alan and Jeff: Once again the two of you (both in combination and separately) have wafted some fresh reasonable insight (and reassurance) into a self-perceived dilemma of mine. But if Jeff regards me as "hellbent," I shudder to think how he characterizes all those other guys out there who have rendered the issue so complicated (read "difficult") over the years as to leave my poor brain struggling for comprehension as I read their varied analyses. Where's my Brownie when I need it? Thanks, again, to both of you. Jim
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... But if Jeff regards me as "hellbent," I shudder to think how he characterizes all those other guys out there who have rendered the issue so complicated (read "difficult") over the years ...
It's simple really...know the technology and bend it to your will. The bottom line is the final image-prolly in a print but not always...some people see the "process" as king. I don't...I see the "process" serving the needs of the creator with making the final image. The image is king, not the process. Other than the creator, who really cares about the process?
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What some people forget is that AA's Zone System depended upon not only metering and exposing the film, but also processing of the film to adjust the tone curve before printing on various paper contrasts. Changing the contrast of the file in development was far more difficult than dealing with post-processing in digital. There is no comparison...to try to convert any sort of zone system (notice the lowercase z) from film to digital is to ignore and misunderstand digital's fundamental difference...raw captures are essentially linear. That means the brightest stop of exposure in a digital capture contains 1/2 of ALL the levels the capture can contain. That is a fundamental disconnect from film...
You would be far better off to discard what you think you know and learn what you need to know regarding digital. Digital ain't film...and trying to apply film-based experience will lead you down the wrong path. Seriously...been there, got the tee-shirt, I don't need/want the scars!
Absolutely correct on all counts. I think we are in wild agreement here.
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Absolutely correct on all counts. I think we are in wild agreement here.
Wow! "WILD" agreement. Oh, you two. Merry Christmas (I almost forgot).
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Zone Sytem survivor signing in here. All I can add for the digital world is one word...BRACKET! Files are free. If 4x5 holders hadn't been so heavy I would have bracketed a lot more in the good old days and been better off for it. You kids don't know how lucky you are.
Well now I can't stop. Best analog for the zone system is some combination of Recovery and/or sliding the right hand part of the LR histogram around. Don't mess with the dark stuff except maybe drag it on screen to correct overall exposure flubs.
Bottom line was that zone system contractions never really worked the way Ansel hoped, and you can see it in the form of the rather impoverished micro-contrast on many of the pieces where he used it. The jazzy Adams images are mostly the ones with normal or expanded development. The simple truth always was...don't block the bright areas, keep the highlights just off the shoulder, and oil the sliders on the drawer with all the burning and dodging gizmos.
Edit...and where was photo-realistic HDR when I needed it? Gawd I needed photo-realistic HDR so bad...
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Zone Sytem survivor signing in here. All I can add for the digital world is one word...BRACKET! Files are free. If 4x5 holders hadn't been so heavy I would have bracketed a lot more in the good old days and been better off for it. You kids don't know how lucky you are.
Well now I can't stop. Best analog for the zone system is some combination of Recovery and/or sliding the right hand part of the LR histogram around. Don't mess with the dark stuff except maybe drag it on screen to correct overall exposure flubs.
Bill,
Not only is it easy to bracket, you have better control over shutter speed and aperture than with the older mechanical cameras. I used to bracket all the time with my Nikormat but of course that was with 35mm film (I wanted to get a 4x5 field camera but never had the money and motivation to do so). Now I can bracket not only with full stops but 1/3 stops and also program the camera to do it automatically. I agree with your thinking about the LR histogram and working in digital is so much easier than 'wet' photography. The one thing I do miss is the magic of seeing the image come up in the developer.
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Once the images were downloaded to Lightroom, you can look at the RAW histogram and compare these to the in camera histogram (as long as you didn't reformat the memory card!).
Just a comment. In Lightroom you don´t have a RAW Histogram. It is a histogram in ProPhotoRGB color space. You need a tool like Rawnalize to see the RAW histogram
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Not trying to be picky here, but in what sense is a 'genuine' raw histogram useful? Surely the data needs a defined space to give it context?
BTW in my photo courses I am starting to use the expression 'capture the data' rather than 'get the shot'. It makes more sense to me to try and capture as much high quality data as possible whilst out in the field and then worry about aesthetic considerations later. ETTR, and bracket if you need to. There is no such thing as a single correct exposure, merely differing qualities of data capture. Worry about the tones when you prepare a file for printing.
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Not trying to be picky here, but in what sense is a 'genuine' raw histogram useful? Surely the data needs a defined space to give it context?
BTW in my photo courses I am starting to use the expression 'capture the data' rather than 'get the shot'. It makes more sense to me to try and capture as much high quality data as possible whilst out in the field and then worry about aesthetic considerations later. ETTR, and bracket if you need to. There is no such thing as a single correct exposure, merely differing qualities of data capture. Worry about the tones when you prepare a file for printing.
Isn't this somewhat the Fred Picker concept and intent I started out with in this thread? Have we perhaps come full circle?
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Yes, exactly. I think the concept is sound.
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Have we perhaps come full circle?
Then what was the reason for the OP?
Fact is, the vast body of knowledge regarding chem based photography is now no longer really directly useful. This is a new paradigm which while having a passing relationship to previous analog technology is more likely to lead a user astray...
Yeah, I know, it's "comfortable" to try to cling to the past...but it is past.
Too bad the guys we're talking about didn't live long enough to see that has now been wrought...I'm sure they would be tickled at the prospect of more easily creating rich imagery.
But at what point do you quit talking about "process" and start making images?
If ya got the time to dwell on the light or timing of the capture, great...do so. If, on the other hand you have fractions of seconds in order to capture the image, the odds of getting a usable capture are MUCH better if you actually click the shutter–as apposed to fiddling with the dials. And yes, you can fix a ton of stuff in post...
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But at what point do you quit talking about "process" and start making images?
Exactly. Fred Picker often responded to technical questions with a big rubber stamp that said "TRY IT!".
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Just a comment. In Lightroom you don´t have a RAW Histogram. It is a histogram in ProPhotoRGB color space. You need a tool like Rawnalize to see the RAW histogram
Since the developer of Rawnalyze has died and no new updates have been made in a few years, is there another tool that would be similar?
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Can anyone point me to two final pictures that show the difference between taking the shot with the heads on exposure vs. ETTR where both were post processed to try to get the best result. Preferably some landscape shot, not a test chart. I'm new to this stuff and am curious to see what everyone's talking about in the result.
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Try this one:
ETTR (http://schewephoto.com/ETTR)
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Jeff: That was an excellent presentation of ETTR. Your explanation made it easy for me to understand. Move as much of the data to the light side without clipping so the sensors can gather more of the info in the shadow areas so the final presentation is cleaner. I have four questions, the first you answered to a degree, but I'd like to flesh it out:
1. What size end product is required to see the noise difference? Certainly you can see it at 300%. But when does ETTR become worth the trouble? Have you done prints at different sizes and compared at "normal" viewing distance?
2. Why are we able to live with shadow areas in pictures that don't have the room on the right to move too? If nobody cares or notices in some of the pictures, why get excited about only some of them?
3. Since you had to brighten the "normal" exposed picture in post processing, doesn't that mean that the exposure wasn't set at the correct point when you exposed the middle picture? If you set it higher to begin with, then the shadow areas would not have had to be processed so bright in the first place so the noise would have been less afterwards.
4. Did you make a 300% comparison of the light areas to see if there was any difference there caused by the move to the right? Your presentation doesn't go into that. The right most histogram shows more clipping before and after the adjustments than the others, I believe.
I ask these questions, because I 'm not a pro and doubt (or hope) I don't need to do this. I'm having enough trouble just with Elements that I would prefer not having to feel I'm doing something wrong just because others are doing it. Thanks for the education. Alan.
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1 Depends...the better the image, the bigger you can go. I chose 300% because you could clearly see the differences.
2 If the image already has a full range such as with a full lit scene, the contrast range will disguise a lot of noise in the shadows.
3. Don't know...I set the camera to expose a normal and plus/minus 1.33. After looking at the image in Camera Raw, I decided to increase the brightness. I matched the overall range with the other exposures. Could the "normal" have been better exposed? Sure. But that's life...you want further info, do it yourself and get back to us...
4. The lighter side of each exposure was just fine after normalizing. Nothing was wrong with the +1.33 exposure that tone mapping didn't resolve. The biggest difference in the results with in the midtones and shadows.
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Not trying to be picky here, but in what sense is a 'genuine' raw histogram useful?
Well, I'd say it's because you
'capture the data' rather than 'get the shot'.
;D
ETTR only means two constraints :
- not clipping the data at one end (even if Jeff's very didactic page shows there definitely may be some leeway here, there are cases where there ain't any due to hue shifts caused by recovery tools),
- and doing the best not to bury the data in noise at the other end of the histogram (and underquantization, though experiments like this one (http://www.luminous-landscape.com/forum/index.php?topic=49200.msg409770#msg409770) let me think we got some fair amount of leeway in this respect).
Worrying about a defined space and context means rather dealing with a rendering of the data, and :
Worry about the tones when you prepare a file for printing.
;D ;D
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I'll accept that ETTR works. But I can't seem to get a practical response as where it will help in the real world because doing it just adds another layer of tweaking and I want to know I'm not wasting my time. If anyone can provide a practical guidepost, that would be helpful. Something like, if you're shooting with a 12meg camera and printing on any paper over 8x10", then you'll be able to see the difference from two feet It doesn't have to be exact, just some guideline. Otherwise I might as well continue to bracket my landscape shots as I have been doing for years not for ETTR but for my mistakes in correctly calculating the exposure in the first place. And if I get to the point when one of those shots would get me better end results had I used ETTR to begin with, I'll have the +1 shot to work with. Anything wrong with that approach.
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Sorry,
I don't think it can be said that way. The idea with ETTR is to keep noise down. Todays DSLRs are pretty clean. Noise is mostly related to photon statistics. Low exposure -> "bad statistics" ->much noise. The noise is mostly present in the shadows. On the other hand noise in shadows may be not very visible. I would say:
- If you have clean shadows you don't need to work on your exposure
- For a high contrast scene ETTR will get very similar to exposing for highlights
ETTR is only applicable to "raw capture", it doesn't really add complexity.
On the other hand, I find DR on todays DSLRs quite impressive. I tried HDR several times, but essentially found that exposing for the highlight (which is essentially is ETTR) still gives very good shadow detail.
Best regards
Erik
I'll accept that ETTR works. But I can't seem to get a practical response as where it will help in the real world because doing it just adds another layer of tweaking and I want to know I'm not wasting my time. If anyone can provide a practical guidepost, that would be helpful. Something like, if you're shooting with a 12meg camera and printing on any paper over 8x10", then you'll be able to see the difference from two feet It doesn't have to be exact, just some guideline. Otherwise I might as well continue to bracket my landscape shots as I have been doing for years not for ETTR but for my mistakes in correctly calculating the exposure in the first place. And if I get to the point when one of those shots would get me better end results had I used ETTR to begin with, I'll have the +1 shot to work with. Anything wrong with that approach.
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Hi,
Do an experiment, if you bracket for say three exposures, select all and apply "auto". Can you see any difference between the exposures? Now which is the best one?
The reason I never bracket is that it gives me three times the work when postprocessing the pictures. What I normally try to do is to take a picture and check the histogram to see if it's all right. If the histogram is less than optimal I adjust exposure and reshoot.
Not saying that there is one and only optimal workflow.
Best regards
Erik
Otherwise I might as well continue to bracket my landscape shots as I have been doing for years not for ETTR but for my mistakes in correctly calculating the exposure in the first place. And if I get to the point when one of those shots would get me better end results had I used ETTR to begin with, I'll have the +1 shot to work with. Anything wrong with that approach.
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I'll accept that ETTR works. But I can't seem to get a practical response as where it will help in the real world because doing it just adds another layer of tweaking and I want to know I'm not wasting my time.
Well, ya know, only YOU can tell if you are wasting YOUR time.
I spent the time to show proof that ETTR can be helpful. That was all I was trying to do. Now it's up to you to decide whether or not it's relevant to your work...I mean really, how much spoon feeding do you need? Go out and try it for yourself.
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Erik: The reason I'm thinking about braketing still is because I'm going to shoot film as well and also to play around with HDR programs to see what they can do in lieu of grad HD filters.
Jeff: Thanks for your analysis of ETTR.
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Hi,
Lightroom and ACR have a very decent "gradient filter", I would play with that before resorting to HDR.
I have also found that luminosity masking in Photoshop is quite useful, from time to time. See this article:
http://echophoto.dnsalias.net/ekr/index.php/photoarticles/46-fixing-sky-with-luminosity-mask
I have done some experiments with HDR, but have not yet found some real benefits. That said I'd say that Photoshop CS Merge To HDR with Local Adaption is quite OK.
Non HDR (from -2 exposure)
http://echophoto.smugmug.com/Special-methods/HDR/HDR/13306153_DcZHj#1002864735_dkeci-A-LB
HDR (using -2, 0 and +2) exposures
http://echophoto.smugmug.com/Special-methods/HDR/HDR/13306153_DcZHj#966794997_wt4h6-A-LB
This folder contains my published HDR samples: http://echophoto.smugmug.com/Special-methods/HDR/HDR
Best regards
Erik
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Erik. That seems relatively normal. The shadows are darker relative to the sky but heck they are shadows. The overall picture looks "normal". That's the kind of thing I'm after not the graphic, cartoony look you usually see in HDR. Just something you might see in real life some time. Tks Alan.
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Since the developer of Rawnalyze has died and no new updates have been made in a few years, is there another tool that would be similar?
There is another possibility to display a RAW histogram (If you know others please share) that involves two tools: dcraw + Histogrammar
dcraw (http://www.cybercom.net/~dcoffin/dcraw/) lets you to convert an unprocessed RAW file into a tiff file, with the -D option
The command I use is: dcraw -v -D -4 -T filename.ext, (where the options mean: verbose, document mode, linear 16 bit, tiff)
Histogrammar (http://www.guillermoluijk.com/tutorial/histogrammar/index_en.htm) is a tool developed by Guillermo Luijk, a contributor on this forum (Gracias Guillermo por tus aportes en este foro y en tu página web),
There is an option to show the RAW histogram provided the tiff file has been processed with the -D option in dcraw
dcraw has been updated recently to support new cameras (as the Nikon D7000). You can find recent compiled versions here (http://www.rawness.es/dcraw/?lang=en)
The attached file shows the raw histogram for the same image in Histogrammar and Rawnalize. The scales of the histogram are different, but you can play with the parameters to get a very detailed graph.
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There is another possibility to display a RAW histogram (If you know others please share)...
My portable Sanho HyperDrive Album will show me a RAW histogram -- and in the field too. However, Sanho has recently discontinued its manufacture and sales, as the LCD displays for it are no longer available from the Sanho supplier. Bummer.