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Thread: A7R and ETTR

  1. #1
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    A7R and ETTR

    Hi !

    I have been using the A7R with my Canon lenses and the metabones adapter, and I am very happy with the results. The 24-70 f/2.8 II is really nice lens on the Sony. The Autofocus is really sloooooow, BUT extremely accurate - no stinkin' micro-adjustments necessary, so I can't complain about that either.

    The only thing that bothers me, is perhaps surprisingly, metering. I tried to use the live histogram (I think it would actually be a cool thing). But when I Expose to the Right (ETTR) on the histogram, I get a lot of blinkies on the final image. Even using the blinkies doesn't seem to be so reliable, as Lightroom shows the image with still some exposure headroom even when the sky blinks. I tried adjusting the Jpeg picture style - it helps get the blinkies closer to what I see in lightroom, but it's still not perfect.

    So how do you do it ? Any tips and tricks ? Is there a way to use the histogram for accurate ETTR exposure ?

    Thanks !

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    Re: A7R and ETTR

    I have exactly the same problem except that it's with both shadows and highlights. I always like to know how near to clipping the raw data is at both ends. No matter how I set the camera up highlights or shadows can be recovered in lightroom even though the camera histogram shows severe clipping. The same applies to the zebra/blinkies displays. The only way to tell is to develop the image in lightroom.

    I thought that setting the camera custom white balance up for universal white balance UniWB would be a solution, giving a good approximation of a RAW histogram with the in camera histogram. Unfortunately trying to set the camera white balance on a magenta target that makes the RGB multipliers all the same value (which would cause the camera histogram based on the jpeg image to be similar to the RAW histogram) doesn't work. The camera returns a white balance error with some of the WB coefficients at full scale ie. out of range of the Sony firmware. If I could make this work I'd accept the yellowish-green in camera image reviews UniWB causes. You can always correct the WB in post if you include a reference target frame. Ideally Sony should give us the option of a RAW based histogram since the dynamic range of the sensor is so large.

    Any ideas, anyone?

    Bob.
    Last edited by Bob Parsons; 4th July 2014 at 13:52.

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    Re: A7R and ETTR

    Bracket, bracket!
    Bill
    Bill CB

    www.billcaulfeild-browne.ca
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    Re: A7R and ETTR

    Quote Originally Posted by miska View Post
    So how do you do it ?
    tuning "zebra" to indicate clipping in raw (and blinkies at the same time in post shot review) shall involve using WB = UniWB and certain combinations of : creative style, zebra value, contrast & saturation, etc, etc

    or you can just use spot metering and positive expocorrection - rawdigger shall help you to find out how your spot metering is calibrated (in your camera) so that you know what expocorrection to dial
    A7RII + FE55/1.8

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    Re: A7R and ETTR

    Quote Originally Posted by Bill Caulfeild-Browne View Post
    Bracket, bracket!
    Bill
    bracketing in continuous mode (when you press shutter release once) will make raw data in A7* cameras a little worse (like 12bit instead of 13bit)... pressing shutter several times is PITA... and cost you some time later, even if you use tools like FRV ( www.fastrawviewer.com from the authors of rawdigger ) that show raw channels info fast (er than other tools)
    A7RII + FE55/1.8

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    Re: A7R and ETTR

    Try: using a high contrast in-camera 'profile'; increasing in-camera contrast in steps to spread the histogram display. Test in LR and reapply.

    I think ETTR is pure urban legend in 2014 that maybe worked at one time - it dates from 2003 - on the market leader, whose cameras were and still are notorious for noisy shadows, but leaving that aside:

    Some reading, note from 2011, well before the 14 stop DR, huge shadow recovery capable 36Mp sensor:

    The Online Photographer: 'Expose to the Right' is a Bunch of Bull

    Ctein is a master printer. Sony would likely agree with him.

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    Re: A7R and ETTR

    Quote Originally Posted by philip_pj View Post
    Try: using a high contrast in-camera 'profile'; increasing in-camera contrast in steps to spread the histogram display. Test in LR and reapply.

    I think ETTR is pure urban legend in 2014 that maybe worked at one time - it dates from 2003 - on the market leader, whose cameras were and still are notorious for noisy shadows, but leaving that aside:

    Some reading, note from 2011, well before the 14 stop DR, huge shadow recovery capable 36Mp sensor:

    The Online Photographer: 'Expose to the Right' is a Bunch of Bull

    Ctein is a master printer. Sony would likely agree with him.
    ETTR is not just about cleaner shadows but about a cleaner image overall, one which is more amenable to manipulation in post. Ctein's main issue with ETTR is his concern about the risk of blowing out highlights, which he feels is not worth the risk with modern sensors since they're much cleaner than previous generations. His opinion is probably correct for many, particularly those who aren't careful enough with ETTR techniques. But it's still a valid technique for those who use it correctly.

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    Re: A7R and ETTR

    Quote Originally Posted by miska View Post
    Hi !

    I have been using the A7R with my Canon lenses and the metabones adapter, and I am very happy with the results. The 24-70 f/2.8 II is really nice lens on the Sony. The Autofocus is really sloooooow, BUT extremely accurate - no stinkin' micro-adjustments necessary, so I can't complain about that either.

    The only thing that bothers me, is perhaps surprisingly, metering. I tried to use the live histogram (I think it would actually be a cool thing). But when I Expose to the Right (ETTR) on the histogram, I get a lot of blinkies on the final image. Even using the blinkies doesn't seem to be so reliable, as Lightroom shows the image with still some exposure headroom even when the sky blinks. I tried adjusting the Jpeg picture style - it helps get the blinkies closer to what I see in lightroom, but it's still not perfect.

    So how do you do it ? Any tips and tricks ? Is there a way to use the histogram for accurate ETTR exposure ?

    Thanks !
    For precise results you'll need to calibrate how the histogram correlates to the underlying raw data. This is done by taking sample photographs at various exposures and then analyzing the raw data in a tool like RawDigger. Here's an article that might get you started.

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    Re: A7R and ETTR

    Quote Originally Posted by horshack View Post
    ETTR is not just about cleaner shadows but about a cleaner image overall, one which is more amenable to manipulation in post. Ctein's main issue with ETTR is his concern about the risk of blowing out highlights, which he feels is not worth the risk with modern sensors since they're much cleaner than previous generations. His opinion is probably correct for many, particularly those who aren't careful enough with ETTR techniques. But it's still a valid technique for those who use it correctly.
    You're probably right in general but I rather have crushed shadows than blown highlights. The problem lies in that crushed shadows even if lacking in details still seem "natural." A funky sky or lights that seem too "off" draws people into them for all the wrong reasons. To each their own but I tend to expose to the left.

    As for the original question - Sony sensors tend to be overly sensitive. I typically shoot with -1/3 Exposure compensation and that tends to be pretty balanced for me in most cases.
    Sony Visible Light & IR Photographer
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    Re: A7R and ETTR

    Quote Originally Posted by philip_pj View Post
    Test in LR
    testing raws in LR/ACR is a heresy... unless you use proper process version and highly custom dcp camera profile (that will have linear curve, properly compensate Adobe's hidden expocorrection and neutralize WB and color transforms)
    A7RII + FE55/1.8

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