Anyone done Carl Weese's 'Paper Towel Test' on the em10?

Discussion in 'Olympus Cameras' started by dancebert, Jun 12, 2014.

  1. dancebert

    dancebert Mu-43 Veteran

    259
    Jan 18, 2014
    Hua Hin, Thailand
    It tests how over or under exposed an image can be and still deliver useful detail from the raw file in post processing. In Carl's words: Time for an objective test. I think this test is vital for anyone with a digital camera because it relates directly to a specific technique that lets you determine the best possible exposure in situations where the tonal range challenges the ability of the sensor. From http://theonlinephotographer.blogspot.com/2006/12/on-testing-new-digital-camera-steps.html
     
  2. OzRay

    OzRay Mu-43 Legend

    Jan 29, 2010
    South Gippsland, Australia
    Ray, not Oz
    I did something like that years ago with my E-1. I set up a paper towel in even lighting and ran a series of exposures to find out exactly the E-1's dynamic range. I then opened the files in Capture One (or it could have been Viewer) and noted where detail in the paper towel was lost at either end. I was very surprised at how wide a range it had but, unfortunately, I don't have the details anymore. I should do something similar with the E-M1 to see how it fares. I found my ancient test: http://www.dpreview.com/forums/post/11058979. That is going back a while, shows how long I've been a 4/3 user (and had to correct a few things in this post). :eek:
     
  3. T N Args

    T N Args Agent Photocateur

    Dec 3, 2013
    Adelaide, Australia
    call me Arg
  4. dancebert

    dancebert Mu-43 Veteran

    259
    Jan 18, 2014
    Hua Hin, Thailand
    Thanks. I intend to do the paper towel test, only question is when. I'll post my results because others may want to know how far to ETTR or L.
     
  5. T N Args

    T N Args Agent Photocateur

    Dec 3, 2013
    Adelaide, Australia
    call me Arg
    ETTLLOL!
     
  6. T N Args

    T N Args Agent Photocateur

    Dec 3, 2013
    Adelaide, Australia
    call me Arg
    Agree, it is a bit perfectionistic. Although I have noticed how well my camera does it with default metering -- so, you could say, no need to worry.
     
  7. Clint

    Clint Mu-43 All-Pro

    Apr 22, 2013
    San Diego area, CA
    Clint
    Not a new concept. I like to use 3 dimensional objects, include a black or very dark item, and a color chart as well. Any textured item will work like terry cloth towels, stuffed animals, etc.

    And once done with that I then do several series with spot, averaging, and ESP/Matrix metering to learn how the camera meters; with the same items from the original series.
     
  8. dancebert

    dancebert Mu-43 Veteran

    259
    Jan 18, 2014
    Hua Hin, Thailand
    Would you share your em10 test conclusions? I'm also curious what in posts 1-7 led you to conclude this is a new technique.
     
  9. janneman

    janneman Mu-43 Veteran

    414
    Dec 6, 2012
    Netherlands
    Jan (John) Kusters
    I have been doing the paper towel test ever since my film days as part of the zone-system testing for films (and now digital camera's).

    Unlike the article, I make a full range, starting at -7 stops and ending with +7 stops. You do not need those extremes, but they might give an indication about the full tonal range, and perhaps even suggest a more or less permanent correction.

    Make sure to turn of everything automatic; iso, colour setting, and of course aperture and shutter speed when doing this test...

    It is also a good idea to combine those shots into one picture afterwards, and see how that looks in whatever medium you choose as output; a computer screen will offer a much wider tonal range than any print for example...
     
  10. David A

    David A Mu-43 All-Pro

    Sep 30, 2011
    Brisbane, Australia
    Don't laugh. Up here in Brisbane with our lighting I found myself having to ETTL to stop the clouds blowing out when I wanted cloud detail quite often with my E-P3. It happens rarely with the E-M5. The fact is, however, that when faced with a scene with an extremely wide luminance range and some bright areas in which you wish to keep detail, the idea of ETTR can easily become ETTL if you wish to keep those highlight details. Put another way, if we could always manage to do without having to ETTL in order to maintain highlights. then I suspect there's also be a hell of a lot fewer HDR photo composites being made.

    ------------------------------------------------------------------------------------------------------------------------------------------------

    To the original question, yes I've done similar tests a couple of times and find them very handy. I shoot RAW and the camera histogram and highlight blinkies warning do not give an accurate indication of where clipping actually occurs with a RAW file. In practice I can recover highlights that the camera shows as clipped with no trouble at all in Lightroom. I originally did this sort of test for the first time some years ago when using Aperture and found the camera warnings reasonably accurate to slightly optimistic but then repeated the test after swapping to Lightroom and found I could recover more highlight detail in Lightroom and that I therefore had a bit more highlight latitude with Lightroom. I've also done similar tests a couple of times comparing different metering modes in my camera so I know how the warnings work when I swap between the whole screen modes and the spot and spot highlight modes.

    I think everyone works differently, and the nature of light can differ in different situations. It can be harsh and contrasty or soft and more diffuse, and that has an effect on highlights. If you're concerned about highlight detail it helps to get a feel for what you can and can't get away with in your sorts of light and with your work practices. I think everyone should occasionally run tests. Not necessarily this test but tests related to where they find issues getting their own images to look right. Experiment with bracketing in problem situations, find out what sort of exposure lets you get the best results. Save your test images. If you change your processing technique or software, take another look at those images and see if your conclusions are still valid or if you can now get a better result some way. Tests don't have to take a lot of time or be difficult to do, but I think you end up getting better results if you occasionally do some tests for yourself.

    As for ETTR, I don't subscribe to it as a technique. The reason for that is simple. The ETTR approach is to expose as far to the right as you can without blowing highlights so if you follow that principle sometimes you expose a fair bit to the right, sometimes a little, sometimes you take the "correct" exposure as determined by the meter, and sometimes you can find yourself actually exposing to the left in order not to blow highlights. I prefer simply to expose for the highlights, simply to give them as much exposure as I can without clipping them. Doesn't matter what the range of the scene is, I simply try to get the highlights right and let everything else fall where it will. That lets me capture the widest range of luminance I can and it seems to work for me. That's my approach.
     
    • Like Like x 1
  11. T N Args

    T N Args Agent Photocateur

    Dec 3, 2013
    Adelaide, Australia
    call me Arg
    Well that is still ETTR. All your attention is on the R.
     
  12. dancebert

    dancebert Mu-43 Veteran

    259
    Jan 18, 2014
    Hua Hin, Thailand
    Two reasons I mentioned ETTL: 1) generate a laugh, 2) Absent other evidence, a one word response that denies the OP's concept is either a troll or not worth replying to.
     
  13. dancebert

    dancebert Mu-43 Veteran

    259
    Jan 18, 2014
    Hua Hin, Thailand
    Exactly why I'm going to do the test. We get thin, high haze much of the year where I live, or a multitude of light types during the rainy season. I expect I'll be doing at least 2 versions of the test

    Thanks for the detail explanation. You probably saved me some false starts.
     
  14. OzRay

    OzRay Mu-43 Legend

    Jan 29, 2010
    South Gippsland, Australia
    Ray, not Oz
    I'm not attempting to prove or disprove anything, I'm entirely ambivalent to the theories of ETTR, ETTL, put your right foot in, take your right foot out etc; I merely provided links to articles where the authors have their own views on ETTR (a long debated concept). You should debate what the authors have stated, not attack the messenger.
     
  15. Misinformation spreads when when content is simply passed on without analysis and verification.
     
    • Like Like x 1
  16. OzRay

    OzRay Mu-43 Legend

    Jan 29, 2010
    South Gippsland, Australia
    Ray, not Oz
    Then analyse and verify, Ye Verily.:biggrin:
     
  17. janneman

    janneman Mu-43 Veteran

    414
    Dec 6, 2012
    Netherlands
    Jan (John) Kusters
    I have been doing a little cutting and pasting to show what can be done with a bunch of paper towel shots.
    Olympus OMD E-M5, ISO 200, f22 1/4000 sec till f4 1/15 sec.
    top row: histograms of the shots as shown by Olympus viiewer 3
    second row:raw to JPEG in Photoshop without any correction
    in red: under and over exposure compared to metering
    third row: in Photoshop RAW auto-corrected JPEGs

    web_onbewerkt_trapjes_olympus_E-M5_2_.

    Things that interested me:
    • -3 till +3 with good detail + black and white (9 stops, too much for prints, fully comparable with Agfa and Ilford films as I used to process them back in film days)
    • with correction -6 till +5 with usable detail (12 stops!), good to know for dodging and burning or one-shot-hdr
    • -2 till +2 exposures are fully salvageable with correction and minimal losses
    • the increase of noise in under exposere is not as dramatic as I expected (not visible in these resized files on the web, but easy noticeable at 100% on my screen)
    • exposure 0 and +1 are best for gentle roll off in high lights (histogram slope right slightly less abrupt) I knew that already and used it in everyday photography.
    • exposure +2 seems to have a more gentle slope to the left; I should experiment with this for well detailed dark sections.
    • Despite calibration with ColorMunki, my screen is slightly too bright (noticed this in prints as well) Hard to correct, but there is shadow detail on my screen that disappears in print, and highlights have more detail in print than on my screen).
     
    • Like Like x 5
  18. Cruzan80

    Cruzan80 Mu-43 All-Pro

    Aug 23, 2012
    Denver, Co
    Sean Rastsmith
    Maybe it is just my monitor, but does the difference seem to be bigger between -2 and -3 vs +2 and +3? Seems like the differences glancing at it are 0 to +2 almost even, -1 and -2 are close to each other, then +3 then -3 in order of change from the previous stop.