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Thread: In-Camera histograms

  1. #1
    Adrian's Avatar
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    In-Camera histograms

    The EOS40D has this display capability. What use to people generally put it to?

    I often find myself snatching photos with little time for careful consideration of exposure. For example, we were at the Chelsea flower show recently and my girlfriend wanted lots of shots to put on a web page for her mother (who lives in Germany). I needed to get a general flavor of the gardens and also record some specific plants (and labels).

    All of this from over a barrier, continually jostled by crowds, and in ever changing light between dark and shade. So I was forever changing the camera settings - and often getting them wrong (as I discovered later on screen!)

    Getting back to my original point - is there an "at a glance" histogram setting that we should generally aim for when pressed for time? One that will give the best chance of achieving an acceptable result in post processing?

    Adrian

  2. #2

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    Re: Camera histograms

    Camera histograms and clip warning lie. They are pesimistic mainly due to white balance (white balance can blow up easily 1 or 1.5 f-stops in some channels, generally R and B). That's why I use a particular WB adjustment which means no white balance at all. When this happens, camera histograms and clip warning become much more reliable under any light conditions and you can trust them much more, specially if doing ETTR.

    For more info: UniWB: reliable camera histograms

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    Re: Camera histograms

    Quote Originally Posted by _GUI_ View Post
    Camera histograms and clip warning lie. They are pesimistic mainly due to white balance (white balance can blow up easily 1 or 1.5 f-stops in some channels, generally R and B). That's why I use a particular WB adjustment which means no white balance at all. When this happens, camera histograms and clip warning become much more reliable under any light conditions and you can trust them much more, specially if doing ETTR.

    For more info: UniWB: reliable camera histograms
    Good points, though generally, in conditions like that, with Auto WB set, it shouldn't be too bad. The ideal histogram (GUI's comments notwithstanding) is one that resembles a Bell Curve with the apex almost but not quite touching the top of the screen, and the ends almost, but not quite touching the edges. That tells you that you have captured all of the data and not lost any to clipping, at least according to the camera. I'm puzzled though why your exposures should have been so far out. In those circumstances I would set up to shoot RAW (for optimal PP WB adjustment) and Program/Auto.

  4. #4

    Re: Camera histograms

    I would usually leave the highlight warning display on when shooting quickly. Remember that this is based on the embedded jpeg and is a warning not a "You've blown it". Nikon tends to flash at you at 245, so there is some room above. The right colour balance is key, especially with skin tnes, the red channel can blow without you realising it, for portrait work, the red highlight clipping display is useful.

    Si

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    Re: Camera histograms

    Quote Originally Posted by tirediron View Post
    Good points, though generally, in conditions like that, with Auto WB set, it shouldn't be too bad. The ideal histogram (GUI's comments notwithstanding) is one that resembles a Bell Curve with the apex almost but not quite touching the top of the screen, and the ends almost, but not quite touching the edges.
    For JPEG shooters, that's right. But for RAW shooters the best histogram is the one that is as exposed as possible (i.e. shifted to the right) but before blowing any info in the highlights of the RAW data, because this assures minimum visible noise and maximum captured DR.

    The UniWB simply helps to find out when you are ACTUALLY starting to blow information.

  6. #6
    Adrian's Avatar
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    Re: Camera histograms

    Thanks for the input. On that particular day I was tending to have a left skewed curve rather than a bell curve. None of the exposures were bad enough to resist post processing and the majority were OK. I do think that the Canon tends to produce rather muted colours (especially of foliage) and I find myself fiddling later.

    In this case I was shooting JPEG because I knew that the images would be going straight onto our web page and that my girlfriend would want them delivered to her mum that weekend. I did not want to spend ages fiddling with RAW files so apart from cropping, pp was minimal except on the images that really were desperate.

    The next big shoot will be next week when we are in Italy, so I hope to get to grips with both cameras much better then.

    Kind regards

    Adrian

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