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Thread: ETTR, LR 4 and x-rite colorchecker passport advice

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    Member sangio's Avatar
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    ETTR, LR 4 and x-rite colorchecker passport advice

    Hi folks:

    Is anyone using and x-rite colorchecker passport reference target and ETTR exposure mode?

    The x-rite folks state the exposure for the target should be "accurate", but with ETTR, the exposure is skewed significantly. The color swatches on the reference target don't look accurate on the LR preview without normalizing the exposure.

    So, I'm wondering, should I normalize the exposure on the target frame first before creating the camera profile, or leave it as is? And should I normalize the exposures on the other images before applying the profile.

    Or should I not use ETTR on the reference target?

    My sense tells me that the exposure on the test frame and other images should be the same before applying the profile, but I'm not sure.

    Any workflow suggestions would be greatly appreciated.

    thanks
    Santo

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    Re: ETTR, LR 4 and x-rite colorchecker passport advice

    Took me a minute to figure out what "ETTR" meant. I don't bother with "expose to the right" stuff. That's just a simple, first order approximation rule of thumb to help you understand how a digital sensor differs from a piece of film.

    I work to expose properly. ;-)

    When doing calibration shooting to develop camera profiles, what I do is first use a tri-band exposure target (you know, the one that has a white, black and gray area) and frame it such that it fills the frame. Correct exposure lands the three spikes on the histogram centered or slightly shifted right. Very slightly, NO clipping on the right. Then I shoot a full size color checker with that exposure setting and use that to set up the camera calibration. Seems to work beautifully.

    Hope that helps!

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    Member sangio's Avatar
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    Re: ETTR, LR 4 and x-rite colorchecker passport advice

    Thanks Godfrey, and sorry for the acronym.

    I'll give that a try once I get one of those exposure targets, the local stores don't carry them; or, I may just dig out my old incident light meter from the bottom of my storage closet (or the junk bin as my wife likes to call it....)

    regards
    Santo

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    Re: ETTR, LR 4 and x-rite colorchecker passport advice

    This is the one I use:

    Photovision 14" Pocket One Shot Digital Target DT14010 B&H

    It doubles as a 14" reflector/diffuser on the other side, and folds into a small package. Handy for $40.

    Godfrey

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    Re: ETTR, LR 4 and x-rite colorchecker passport advice

    Yes, normalize the exposure.

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