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ETTR - E-M1 and Adobe RGB vs sRGB

Discussion in 'Olympus Cameras' started by tomO2013, Dec 27, 2013.

  1. tomO2013

    tomO2013 Mu-43 Top Veteran

    799
    Oct 28, 2013
    Hi guys,

    I am interested in your opinions.

    I've fairly recently discovered the ETTR approach to digital photography. Indirectly I may have accidentally been doing this by setting my exposure value based on the reflected light from the palm of my hand and putting my hand at 1 above medium grey (caucasian skin).
    However I was recently reading Pekka Potka's blog here :
    http://www.pekkapotka.com/journal/2012/6/14/olympus-e-m5-exposing-to-the-right-and-lightroom-41.html

    In it he recommended setting the colour space to Adobe RGB and the highlight warning set to 245 which equates to approx 96% of pure white value.
    However I'm also aware that the Adobe RGB colour space is a lot wider and that working within this color space when you don't have an adequate / supporting monitor and printer will cause inconsistent results in your prints to what you see on screen.

    Is there an added advantage to enabling the Adobe RGB colour space when shooting with ETTR technique?

    Thanks,

    Tom.
     
  2. b_rubenstein

    b_rubenstein Mu-43 All-Pro

    Mar 20, 2012
    Melbourne, FL
    One has nothing to do with the other.

    Your method of metering is a old, established way of essentially taking an incident light meter reading with a reflected light meter. It is more accurate to use an 18% grey card than the palm of your hand. It also has nothing to do with ETTR, which is nothing more than raising the exposure (signal) as high above the electronic noise in the camera, without clipping highlights. This was a much more useful technique in the early days of digital photography when cameras had a very limited dynamic range.
     
  3. entropicremnants

    entropicremnants Mu-43 All-Pro

    Jul 16, 2012
    John Griggs
    ETTR is still very useful actually, but the OP's method doesn't seem to be using it as you noted.

    First, keep in mind that when one shoots JPG, the ETTR is nearly useless for many scenes. The JPG engine doesn't properly figure out what you're doing and throws away highlights and makes an unnaturally bright picture that has lost too much highlight information. So in RAW, it shouldn't matter which color space you use which makes the sRGB/aRBG question not relevant...

    ...EXCEPT: Pekka is a careful investigator. What he found (and I use to shoot an E-M5 using his methods) is that the histogram and "blinkies" are generated not directly from RAW sensor data, but from the constructed JPG for preview in the LCD and EVF. He therefore has you setting the camera up to give you the most reliable indicator for clipping in certain color regions by setting the color space.

    If you've ever used for instance a white-only histogram to set exposure, you've probably run into the problem where the histogram looked okay, but the resulting shot -- even in RAW -- had a certain color channel blown out. This occurs because the sum or the colors isn't high enough to trigger a "blinky" but the individual channel is maxed out. He is no doubt getting you to set the camera up to minimize problems in this area.

    So, if you follow his method, you will likely end up with unusable JPG's. It's simply not necessary to use ETTR for everything -- but "at the margins" you'll find it helps a great deal. NO camera ever has enough dynamic range yet to cover everything you see. If that were only true, I wouldn't have to use photo-realistic HDR to capture some of my urbex stuff, lol.
     
  4. Clint

    Clint Mu-43 All-Pro

    Apr 22, 2013
    San Diego area, CA
    Clint
    Almost all of the needs to use ETTR have been negated to a great extent by shooting RAW and using a large processing color space such as ProPhotoRGB, as with Lightroom. If you calibrate and use color profiles for your monitor and use output devices, programs like Lightroom pretty much handle all of the rest of color management for you.


    In essence ETTR is no more than the Zone System of placing light values so that they will produce the desired results in the final product, after using the appropriate manipulations. To do that properly and routinely takes a lot of learning and experience. If you do not use a color managed workflow, ETTR gains you very little and can just as easily end up destroying more image qualities than if one just started with and output an sRGB image.


    Using AdobeRGB is a primary a benefit for those that have their products used in CMYK printing processes. It allows remapping colors to the highly reduced color gamut of CMYK while reducing artifacts and maintaining smooth graduations that would not be possible when altering sRGB gamma and tone curves in an image.
     
  5. tomO2013

    tomO2013 Mu-43 Top Veteran

    799
    Oct 28, 2013
    Hi again,

    Thanks for the responses.

    I think mentioning metering off of my hand was somewhat of a curve ball in the context of this conversation :) I know it has nothing directly to do with ETTR, - it was mentioned more from a point of view of a relatively reliable (in good light anyway) technique that I have/had been using at presence in the absence of a grey card!

    I do understand the logic behind ETTR - essentially to capture as much information as possible in the RAW file. Similar to utilizing the zone system with film and thinking at the moment of capture of what medium you would ultimately like to print out on.
    My questions was not so much one of the the reasoning behind the ETTR approach - but more a question of specifically why Pekka Potka was explicitly setting the colour space to Adobe RGB when ultimately we are shooting in RAW. But you nailed in on the head entropicremnants, it was obvious! - the screen itself is a Jpeg representation of the RAW data.

    Thank you for your help guys. I'm playing around with ETTR and finding that it really does make a difference - however one change to my workflow is that I am explicitly telling LR to ignore the Exif info and to use RGB output when processing (my equipment isn't calibrated to Adobe RGB ).
     
  6. entropicremnants

    entropicremnants Mu-43 All-Pro

    Jul 16, 2012
    John Griggs
    Incorrect. ETTR is a way of maximizing signal to noise ratio. It actually has nothing to do with the zone system other than it's a method of getting the exposure you want.

    A "color managed" workflow is a great idea -- but that's pretty easy these days and if you use professional printing services it's trivial. ETTR does not affect it at all.

    RAW is a necessary component of ETTR and you apparently did not read my response carefully, and you certainly haven't read Pekka Potka's article at all as your assertions are inaccurate about the ETTR methodology he proposed.
     
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  7. b_rubenstein

    b_rubenstein Mu-43 All-Pro

    Mar 20, 2012
    Melbourne, FL
    :bravo-009: Thanks you.
     
  8. The purpose of ETTR is to to reduce or remove the need to push (increase exposure) the darker areas of an image in processing and ideally will require the image to be pulled (reduce exposure).

    Pushing = more noise.

    What you want is to reliably know where the right end of the histogram is so that you don't lose any colour or detail that you don't want to (for example, there is no point trying to meter off and retrieve the centre of the sun if it is in the frame. It looks weird when it is grey). My favourite method to judge how far you can expose to the right is to use the jpeg engine to your advantage by maximising the dynamic range that it will record. Set gradation to auto, choose a low contrast and saturation picture mode like "natural" and even reduce contrast as well. This puts the dynamic range of the jpeg as near as possible to the raw and combined with the accurate exposure preview on Olympus cameras and exposure aids like the highlight "blinkies" will be about as accurate a guide as you can get.

    The use of ETTR is probably more relevant now than ever hecause the broader dynamic range of modern sensors gives you more headroom to increase exposure beyond the metered value, although on the other hand sensors are also less noisy such that pushing shadows is less harmful to overall IQ. The little point of metal that protrudes from under the front dial on my E-M5 has had the paint worn off because I have adjusted the exposure compensation so much on that camera.
     
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  9. flash

    flash Mu-43 Hall of Famer

    Apr 29, 2010
    1 hour from Sydney Australia.
    Gordon
    Lots of talk about ETTR, whch the OP seems to understand and not much answering the actual question.

    Yes.

    That technique will give you a somewhat more accurate way of setting your camer up to display a histogram that show clipping more accurately. Obviously you can't shoot usable in camera jpegs using this method. It's only a way to get the camera to show raw data clipping more accurately.

    As far as your computer and calibration, it's irrelevant. The set up in camera is only for in camera jpegs, which is also what the camera sets cipping warnings off. The actual raw data doesn't have a space until you assign one when exporting the file from Lightroom and you'll still be using the Melissa working space in LR. So you won't be doing anything to the raw data by seting an aRGB space in camera.

    Gordon
     
  10. No, not directly, but the whole trick* of ETTR is figuring out a reliable method of establishing where the "right" is. Pekka Potka proposes a scientific method of doing it, whereas I use a more practical method.

    *The exposing, not the processing.
     
  11. Malo1961

    Malo1961 Mu-43 Regular

    87
    May 17, 2010
    The Netherlands
    I seem to recall an article on The Luminous Landscape website about using ETTR . I think it's found under tutorials or something like that. In a nutshell this is how it was explained.
    ETTR is only useful if you shoot RAW. The idea is getting in as much information as possible in each raw file. Hence.......Expose as much to the right of your histogram as possible (without overexposing)
    Why?? Most of the image date is found in the lighter parts of each file. The more you concentrate on the lighter values, the more you open up the darker tones without the need to force them open en thereby
    create noise. Now the tricky and often forgotten caveat. The next I have tested a couple of years ago when I started using the ETTR technique.
    The histogram on your LCD or EVF is based on the in camera produced jpeg. This....to my knowledge is true for almost every digital camera on the market. (perhaps there are some exceptions found on pro medium format digital
    backs, but I am not sure. However.....

    If you want to evaluate your exposure using ettr as a way to get a near perfectly exposed raw file and base your decision on the in camera produced jpeg you have to take some vital steps.
    Remember....The manufacturers goal is producing a very good looking picture on the LCD. This to feed the hunger of all those Chimpers out there. LOL
    But......This means, the internal settings are often spiced up, simply to make that picture look really good. Sharpness + 1/Contrast +1/Saturation +1 etc,etc.....
    So based on that fantastic looking LCD picture and histogram you decide how far you are going with ETTR. Seems logical, right???
    WRONG !!! If you want a histogram that represents values as near to those values of a raw file as is possible you should forget about how good the picture looks on the screen .
    The screens histogram only should be used to look at the histogram.

    Therefore: Set every setting to 0 or even better to minus one. And with every setting I mean: Saturation set on 0/ Contrast on Minus one/ Sharpness on 0 or minus 1
    These 3 settings have the most influence on how the in camera jpeg looks and therefore the way how the in camera histogram divides its individual values.
    As I mentioned before, I have tested it . It's very simple to do yourself. Shoot raw and base your exposure using the in camera settings set to default. Expose as much to the right as possible.
    Ohhhh....obviously set the camaras colorspace to adobe RGB instead of sRGB. Now ...transfer your raw files to LR or PS and open them. You will see that all of the opened raw files will show a histogram with 1 full stop or more latitude
    to expose even further more to the right. Believe me, it is true. I was shocked, the first time I noticed that, but it makes sence. Therefore....If you want to use ETTR as your main exposing technique:
    A: Shoot Raw only
    B: Use Adobe RGB as in camera colorspace (it holds more data as sRGB) Use Profoto RGB in your Raw converter)
    C: Set Saturation, Contrast and Sharpness to 0 or minus 1
    D: Forget the image on the LCD and concentrate on the histogram.
    E: This way your on screen pictures will look like rubbish, but the histogram which is based on that displayed picture data will come much closer to that of a histogram of a RAW file.

    PS, Obviously we all use Olympus for it's known and highly regarded in camera jpeg files it is capable of producing.
    I do want to state the following: All the writing above is not a attempt to convince everybody out here to shoot raw instead of jpeg. Or re-fuel the Old and so boring Raw vs Jpeg discussion. So don't even try it in your replies, OK?
    But ...If you shoot Raw on principle and want to get in the ETTR technique, the above mentioned method should be something you at least should give some thoughts about. Nothing wrong with that,
    If all of the above doesn't work for you, and you are fine with the jpeg's the camera produces for you keep on doing that. Hell.....You sure will spend more time in the field and less time behind the pc. And that's always a good thing.

    Good luck, if needed.
     
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  12. William Porter

    William Porter New to Mu-43

    5
    Jan 3, 2014
    no :)

    Tom,

    In a word, NO. :)

    Two points:
    1. The AdobeRGB vs sRGB choice MAKES NO DIFFERENCE FOR RAW CAPTURE. It only matters when you export your processed files to JPEG.
    2. The question "To ETTR or not to ETTR?" IS IRRELEVANT UNLESS YOU'RE SHOOTING RAW.

    So you have a choice. Either (a) shoot jpeg and worry about color space, or (b) shoot raw and worry about whether you should expose to the right. You don't worry about both.

    While I'm at it, I'll tell you what I've learned, after shooting raw and attempting to make sense of ETTR for five years or so. (I read the article when it first appeared and immediately thought another Epistle of St Paul had been discovered.) My conclusion is that shooting raw is the only way to go; but that ETTR, while the technical underpinnings seem to make sense, is, as a practical matter, nonsense or very close. I've given up on it completely.

    This article has a pretty good analysis:

    http://chromasoft.blogspot.com/2009/09/why-expose-to-right-is-just-plain-wrong.html

    There are other articles on the 'net explaining why ETTR is, as a practical matter, simply not useful.

    To summarize:
    • Shoot raw, whenever possible. (You can shoot raw + jpeg, too, and see if you like the jpegs. And if you find the jpegs are satisfactory, then stop shooting raw.)
    • If the scene has less exposure range than your camera (low contrast) then you may want to expose just a LITTLE to the right, but it probably won't make much of a difference.
    • If the scene's exposure range equals or exceeds the capture range of your camera, then expose "normally," that is, get the midtones in the middle of this histogram and do your best not to blow out SIGNIFICANT highlights.

    That's it. I love Michael Reichmann and have learned a lot from Luminous Landscape. But on this one he's thinking way too hard.

    Will
     
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  13. David A

    David A Mu-43 All-Pro

    Sep 30, 2011
    Brisbane, Australia
    Not quite correct.

    You're right that the choice between Adobe RGB and sRGB makes no difference to RAW files but it does affect how the camera converts the data to JPEG for display on your camera screen/in the viewfinder and it is that JPEG that is used as data for the metering software. What you should never do with ETTR is overexpose your highlights, but you want to give them as much exposure as possible without overexposing them. Adopting the Adobe RGB setting means that the camera's meter is working with data that more closely approximates the dynamic range of a RAW file than the sRGB JPEG conversion would provide, so it makes your camera's light meter indications a bit more reliable if you're shooting RAW. The Adobe RGB setting gives you a bit more reliable info on how far to the right you can expose than the sRGB setting would, and that's the point of using that setting.

    It's also worth noting that regardless of whether you are going to use ETTR or not, you will potentially get better meter accuracy with the Adobe RGB setting than you will with the sRGB setting if you're shooting RAW. You have to choose either Adobe RGB or sRGB. It really only makes sense to choose sRGB if you're shooting JPEGs and want to use your files straight out of camera on the net or with an sRGB display of some kind because choosing sRGB under those circumstances will adapt your meter's operations to the sRGB range and give you better results in those circumstances. If you're going to do any kind of processing at all, set the camera to Adobe RGB.

    As for ETTR and JPEGs, well ETTR can still be relevant but it won't be relevant anywhere near as often. The dynamic range of your data is less when you're saving in JPEG so it's far less likely that you'll be able to shift your highlights to the right by increasing exposure without clipping them but if you can, then doing so will get you a bit better signal to noise ratio in the darker parts of the scene. You will have to adjust your exposure setting for the file in post processing, however, so ETTR makes no sense at all if you want to use JPEGs straight out of camera with no processing. What that means in practice is that ETTR is pretty useless as an approach if you're shooting JPEG but on the rare occasion every now and then it may be helpful.
     
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