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Thread: Pushing the ISO limits of the E-M1, ETTxR

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    Default Pushing the ISO limits of the E-M1, ETTxR

    Two shots, one .38EV underexposed, the other 1.82EV overexposed, in other words, ETTextremeR.
    Exposure and WB balanced on the front of the outlet. Same light sharpening and moderate NR in LR5. ISO 25,600. Everything the same, basically.




    So, who says ETTR is a bunch of hooey?

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    Default Re: Pushing the ISO limits of the E-M1, ETTxR

    Now, can you explain this to me like I'm a 4 year old? What exactly did you do?
    Olympus E-M1 Mk II
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    Default Re: Pushing the ISO limits of the E-M1, ETTxR

    ETTR means "expose to the right", which means, getting as much of your histogram as possible pushed to the right as more information is stored in the higher bands than in the lower bands. The higher you push the ISO the more important it becomes because the noise increases in the dark areas more than in the lighter areas. So basically, all you have to do is over expose just short of clipping the highs, (unless they are in a part of the image where it doesn't mater) and bring the image back down in post. Under exposing and bringing up spells disaster in the darks.
    Here is what the two histograms look like before processing:
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    And here the lighter one brought back down:
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    There are a number of good articles on the internet about ETTR.

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    Default Re: Pushing the ISO limits of the E-M1, ETTxR

    I have begun using ETTR method myself. Makes a difference.


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    Default Re: Pushing the ISO limits of the E-M1, ETTxR

    Yup! And the higher you push the ISO the bigger the difference it makes. So "correct" exposure at ISO 200 and at ISO 25,600 are two very different kettles of fish.

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    Default Re: Pushing the ISO limits of the E-M1, ETTxR

    But when you do overexpose, don't you get slower shutter speed or higher ISO than if you expose correctly?
    Olympus E-M1 Mk II
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    Default Re: Pushing the ISO limits of the E-M1, ETTxR

    Yes, you do, and this is an extreme example just to see what happens. Usually .3 to .7 EVF is sufficient. These two are two stops apart.
    In theory you gain more than by lowering the ISO and exposing "correctly". ITTR is normally done at base ISO anyway. Have to test it for myself. Must be something to it as it has become standard practice in digital photography. Just the opposite with slide film where it is better to lightly underexpose than to over expose. B+W it was better to slightly over expose. Thin negatives were a horror to work with.

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    Default Re: Pushing the ISO limits of the E-M1, ETTxR

    So for the above 2 pictures, what exactly was the shutter speed / aperture / ISO?

    I understand ISO is the same for both, but the first picture is better looking because you overexposed and then brought down highlights in post? I am going to have to try this
    Olympus E-M1 Mk II
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    Default Re: Pushing the ISO limits of the E-M1, ETTxR

    Same f-stop. 1/500 for the "normal" exposure, that is, what the camera told me to use, and 1/125 for the "over exposed" shot. Both ISO 25,600, f/6.7 at 300mm.

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    Default Re: Pushing the ISO limits of the E-M1, ETTxR

    You used raw on these shots, not jpg, right? Seems as though using jpg would limit a lot of what you could pull out of the deliberately over-exposed light areas.

    Also, why did you use such a wimpy ISO (25,600)?
    Rich
    Olympus E-M10; Panasonic GM5
    m4/3 lenses: Oly 75-300; Oly 14-42 f3.5-5.6 II R; Oly 17 f1.8; Oly 40-150 f4.0-5.6 R; Oly WCON-P01 adapter; Rokinon f7.5 fisheye; Sigma 19 f2.8; Pan 20 f1.7; Pan 12-35 f2.8; Pan 12-32

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    Default Re: Pushing the ISO limits of the E-M1, ETTxR

    25,600 was all I had!
    Yes, raw.
    It is not about the highs but about what can be pulled up out of the shadows. And there, jpg can't compete with raw.
    Last edited by Daniel Bradley; 12-17-2014 at 05:36 AM.

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    Default Re: Pushing the ISO limits of the E-M1, ETTxR

    Here is an interesting demonstration of ETTR. Set jpg to see what the camera saw and raw to see what can be saved. Two settings, ETTR and ETTR-1 EV show the effect of ETTR.
    Also shows how much Canon is (still) lagging behind Nikon (Sony) in DR. At higher ISO settings the difference is not so great, but there other factors come into play. This is a pure DR demonstration at base ISO.

    Oops, forgot the link....
    http://www.dpreview.com/reviews/canon-eos-7d-mark-ii/13
    Last edited by Daniel Bradley; 12-17-2014 at 12:21 AM.

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    Default Re: Pushing the ISO limits of the E-M1, ETTxR

    Well, I now understand that shooting ETTR gets you more DR to work with if you shoot both files at same ISO.

    But if you shot one picture at 1/500 and ISO25,600 and the other at 1/125 at ISO25,600, you could have just shot the first one at 1/125 as well and then you could use ISO 6400?

    I guess I see the point of this if you are shooting both pictures at ISO200 and you want to minimize noise to as low as possible, you slightly overexpose and then pull back the highlights in RAW. However, in these kind of situations, such as a sunset photo, I find that I am usually clipping both highlights and shadows, and if you are already doing RAW processing, wouldn't bracketing achieve better results?

    And yeah, Canon is definitely lagging behind Nikon.
    Olympus E-M1 Mk II
    7.5mm f/2.0 - 12mm f/2.0 - 17mm f/1.2 - 17mm f/1.8 - 25mm f/1.8 - 45mm f/1.8 - 56mm f/1.4 - 9-18mm - 14-150mm II

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    Default Re: Pushing the ISO limits of the E-M1, ETTxR

    What I suspect is, Edmunds, that a picture taken at say 6400 and exposed one stop to the right, which would be the same as shooting 3200 normally, will come out better because the sensor will have been filled better. Remember that ISO settings have no effect on the sensor. Only the exposure does that. ISO is setting the gain for the amplifiers AFTER the sensor. So the trick is to get as much information, i.e. light, onto the sensor without the "photo buckets" overflowing and causing clipping and light noise.

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    Default Re: Pushing the ISO limits of the E-M1, ETTxR

    Quote Originally Posted by Edmunds View Post
    if you are already doing RAW processing, wouldn't bracketing achieve better results?
    By bracketing, do you mean by increasing and decreasing the shutter speed/aperture? Or do you mean by increasing and decreasing the ISO? If you mean increasing and decreasing the shutter speed/aperture, isn't that what Daniel is doing (keeping the ISO constant)? And also what the camera would do if you used auto-bracketing.
    Rich
    Olympus E-M10; Panasonic GM5
    m4/3 lenses: Oly 75-300; Oly 14-42 f3.5-5.6 II R; Oly 17 f1.8; Oly 40-150 f4.0-5.6 R; Oly WCON-P01 adapter; Rokinon f7.5 fisheye; Sigma 19 f2.8; Pan 20 f1.7; Pan 12-35 f2.8; Pan 12-32

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    Default Re: Pushing the ISO limits of the E-M1, ETTxR

    Quote Originally Posted by RAH View Post
    By bracketing, do you mean by increasing and decreasing the shutter speed/aperture? Or do you mean by increasing and decreasing the ISO? If you mean increasing and decreasing the shutter speed/aperture, isn't that what Daniel is doing (keeping the ISO constant)? And also what the camera would do if you used auto-bracketing.
    By bracketing I mean changing shutter speed. That is different because you then stack several images to get back highlights/shadows.

    Quote Originally Posted by Daniel Bradley View Post
    What I suspect is, Edmunds, that a picture taken at say 6400 and exposed one stop to the right, which would be the same as shooting 3200 normally, will come out better because the sensor will have been filled better. Remember that ISO settings have no effect on the sensor. Only the exposure does that. ISO is setting the gain for the amplifiers AFTER the sensor. So the trick is to get as much information, i.e. light, onto the sensor without the "photo buckets" overflowing and causing clipping and light noise.

    Interesting idea.

    I went ahead and did that. I took one picture at f/5.6, 1/15 and ISO3200 and one with f/5.6, 1/15 and ISO 6400. The latter is then 1 stop overexposed. I opened it in RAW and brought it down 1 stop.

    Here are the results:





    It does not seem like any one image is cleaner
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    Olympus E-M1 Mk II
    7.5mm f/2.0 - 12mm f/2.0 - 17mm f/1.2 - 17mm f/1.8 - 25mm f/1.8 - 45mm f/1.8 - 56mm f/1.4 - 9-18mm - 14-150mm II

  17. The Following User Says Thank You to Edmunds For This Useful Post:

    RAH (12-18-2014)

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    Default Re: Pushing the ISO limits of the E-M1, ETTxR

    The first one is margenally sharper, that is, less noisy, and has slightly richer colors. That is the 3200 shot, right?

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    Default Re: Pushing the ISO limits of the E-M1, ETTxR

    Yes, the first is ISO3200 and the second is ISO6400.

    I did too notice that it is sliiightly better, but I wouldn't really say "better". I think this should be repeated with ISO800 vs ISO1600. Maybe then we'll see a real difference because honestly both of these are not very good.
    Olympus E-M1 Mk II
    7.5mm f/2.0 - 12mm f/2.0 - 17mm f/1.2 - 17mm f/1.8 - 25mm f/1.8 - 45mm f/1.8 - 56mm f/1.4 - 9-18mm - 14-150mm II

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    Default Re: Pushing the ISO limits of the E-M1, ETTxR

    Have to try at base ISO (200) also. I would too but my E-M1 is in for repairs.

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    Default Re: Pushing the ISO limits of the E-M1, ETTxR

    The second shot seems to have a purple hue to it. Like the exposure, the shadows, have been pushed to far.


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    Default Re: Pushing the ISO limits of the E-M1, ETTxR

    Exactly. No information left in those bands.

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