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Accurate Settings


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#1 Andrew Uio

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Posted 02 September 2006 - 03:10 PM

Howdy,

I've often wanted to put a camera into a sort of "accurate" mode where, except for white balance, no modifications are performed to the image. No saturation changes, no sharpening (just best interpolation possible), no contrast curve, etc. Kind of a partial analog of "RAW" mode in photography, which many people find quite useful.

With every camera I've ever seen, you can only control the levels of settings, but it is never clear how to disable them. For example, does the middle setting of saturation mean no modification, or does it mean adjust saturation to what consumers typically want? I'm guessing it is the later. But that fact never seems to be documented.

Has anybody seen a camera where you really know what operations are being applied to the image, and can easily disable them completely?

Cheers,
Andrew
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#2 Simon Wyndham

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Posted 03 September 2006 - 04:25 AM

On the pro cameras you can disable most functions.

*BUT* theres a catch. You NEED a lot of those functions. You won't achieve the equivalent of a stills camera RAW mode. The only way to achieve a similar image to that in video is to use a camera like the Viper Filmstream, or the Andromeda mod to the DVX100.

If you turn off all the functions on a video camera, such as gamma, you will have an extremely limited image with really bad contrast ability.
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#3 Michael Collier

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Posted 03 September 2006 - 04:39 AM

The only camera that can disable every bit of DSP is the viper. Every camera has a greenish image (because of the effeciency of the color filters on either a bayer or prism 3CCD system) and so even if there were a way to disable the 'extra' features, there would still be a look up table to apply white ballance.

The problem with taking all DSP out is you limit after-the fact color correction. Most times information is recorded compressed, which means you gain a lot by defining the image prior to shooting. With the DVX or cameras in this range its a requirement. With pro cameras in both SD and HD range it is a highly recomended practice. The bottom line is there should be no 'dumb shooting'. Most of my work (today) is shot on an old beta. But on that I have pedastal lowered to -2 and detail at 40. I found the look I like and only change it if I need more range, or if I have to push gain up I can lower detail. Menu adjustments serve to put a good look before loosing information, then you can touch it up a bit in post.

My final point why this would be a bad system (unless recording native CCD information) is that you should have a good idea what you want prior to shooting. A little bit of commitment is a good thing. You can change things back and forth and anything that hangs off that is jepordized. If you create a solid look prior to shooting, you will know exactly how to set the camera to ballpark it.
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#4 Andrew Uio

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Posted 03 September 2006 - 05:33 PM

Howdy,

Thanks for the replies. I didn't really mean to imply turning off things like gamma or interpolation of the bayer array. Just the more subjective settings, like the ones I mentioned: saturation, contrast, sharpness. All the prosumer cameras I've seen allow you to adjust them, but never seem to tell you what to set to get no saturation change, no contrast change, no sharpness change, etc. So I guess that is not really a RAW image.

As an example of why I personally want saturation completely off is that I prefer to perform color balance in post before saturation, and saturation applied in camera apriori will be difficult to undo and mathematically will interfere with color balance across the range from lights to darks.

Regarding gamma, it is obviously important for range compression in the encoding process. It would be nice if cameras would document their gamma curves they apply. I've written a lot of video filters that ungamma the image to operate in linear tone space, and I usually just have to assume that the gamma is 2.2.

Regarding compression, won't you get better compression with saturation, contrast and sharpening off? All those attributes tend to "spread" the image, which hurts compression and introduces more artifacts. Another reason I would like them off in the camera, since I can easily perform them later, with much greater flexibility.

I'd still be curious to hear about any prosumer cameras that are a little more clear about what is being applied and how to disable it.

Cheers,
Andrew
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#5 Joshua Provost

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Posted 15 September 2006 - 05:57 PM

Andrew,

It's not so much about disabling those functions. You can't disable saturation. It sounds like what you are looking for is to get the camera to acurately reflect reality without altering it. For that, you need a DSC chip chart and a waveform monitor. Depending on the camera, you can use the settings (chroma, phase, temp, gamma, matrix, etc.) to get pretty close to reality.

By default, most cameras are overly contrasty, overly saturated, and then each manufacturer tends to have it's own unique color cast, even when white balanced against the same reference.

Josh
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#6 Simon Wyndham

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Posted 16 September 2006 - 10:04 AM

By default, most cameras are overly contrasty, overly saturated, and then each manufacturer tends to have it's own unique color cast, even when white balanced against the same reference.


Sometimes I find the opposite. I think the XDCAM is a bit flat out of the box for example, and certainly not oversaturated.

Usually a 'technically' good picture is not the most aesthetically pleasing. Hence why many shows these days ramp the contrast and saturation up. I don't think there is such a thing as overly contrasty and overly saturated (unless we are talking about illegal levels on a scope) because different looks suit different programmes.

It is good to have a neutral starting point though. Hence DSC charts.
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