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contrast with a small dynamic range?


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#1 Delorme Jean-Marie

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Posted 29 August 2005 - 08:14 AM

hi
here is my wonder of today.
lighting for dv cam such as agdvx 100 allows a small latitude... somthing like -2 stops and +1 stop (correct me if you experienced this camera latitude whith a different result )
it means that if i do not want to burn the hilights, and shut of the low lights i have to stay in this range.
my question is do we realy feel differences of contrast of 1/4 or 1/3 of a stop or do we have to work on a higher scale like 1/2 a stop.
my question is vs film wich has a large latitude compare to 4:1:1.
i believe it depends how "contrast" you want to be? but i doubt that we can notice, by eye, a difference of 1/4 or 1/3 of a stop.
thank you to share your experience in this point i hope i made myself clear...
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#2 Joshua Provost

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Posted 29 August 2005 - 10:20 AM

An XL2 or DVX100A have more than 4 stops of latitude. The DVX100A, I believe, has more like 6-8 stops, and there are ways to tweak the gamma curve to get even more. Here is an article comparing the XL2/DVX100A/FX1, including information on latitude.
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#3 Michael Nash

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Posted 29 August 2005 - 11:30 AM

Almost any video camera has more than 2 stops of underexposure. The DVX-100 has a dynamic range that can see probably more like 4 stops under before a gray card goes black. The highlight range is pretty compressed, though. And has been mentioned you can tweak the response curve of the camera.

But once again let's not confuse DYNAMIC RANGE (the range of brightness the camera can capture), and LATITUDE (the amount you can over- or under-expose an image and be able to recover a "normal" looking image). When you say a camera has "6-8 stops of latitude" you're saying it can be over- or under-exposed 3-4 stops and still give you a recoverable image, which simply isn't true of course. People may disagree with the term "dynamic range" being applied to video, but "latitude" is clearly defined, and it's not what we're talking about here.

But regarding lighting in 1/3 or 1/2 stop increments; with video what-you-see-is-what-you-get. The way it looks on a properly calibrated monitor is the way it will appear later on. Don't rely 100% on the camera's LCD though, it too has to be set up properly and the shadow detail changes significantly with viewing angle.

4:1:1 compression has nothing to do with contrast or the dynamic range of the camera though, it only refers to the color.
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#4 Delorme Jean-Marie

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Posted 30 August 2005 - 04:17 AM

thank you mr nash for lighting the darkness of my knowledge, it's a lot more clear for me now.
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