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-   -   S Log Exposure/LUTs (https://www.dvinfo.net/forum/sony-xdcam-pmw-f3-cinealta/502235-s-log-exposure-luts.html)

Tony Brennan November 1st, 2011 10:54 PM

S Log Exposure/LUTs
 
The in built LUTs affect the zebras and brightness readings on the F3 viewfinder and LCD. When using the LUTs and recording the 444 S log output, how do you judge correct exposure in the camera? Is the only way with an external 444 waveform monitor?
It would be great to be able to send the LUT out of the SDI and still view the full S Log image in LCD or viewfinder of the camera.
For example, if you expose S Log so that it just reaches 100%, then turn on a LUT, the camera would have to be stop down further to hold the same highlight information. So if you make eposure judgments with the LUTs on you could be sacrificing latitude.
How is everyone judging exposure with SLog?

Alister Chapman November 2nd, 2011 06:04 PM

Re: S Log Exposure/LUTs
 
The histogram is not effected by the LUT's.

Tony Brennan November 3rd, 2011 02:11 AM

Re: S Log Exposure/LUTs
 
Thanks Alister,

I will check that out. Although the histogram is not my favorite exposure tool.

Alister Chapman November 4th, 2011 08:13 AM

Re: S Log Exposure/LUTs
 
Oops. I got that one wrong. I checked today and LUT's do change the Histogram. Sorry my bad.

Of course.... if you have a Convergent Design Gemini you can add a LUT to you monitor out with that.

Tony Brennan November 4th, 2011 03:00 PM

Re: S Log Exposure/LUTs
 
It's a pitty as it does make the in built LUTs in the camera less use full. Not being able to correctly monitor exposure at the camera will make the LUTs useless to me. I will just have to use monitors with a LUT. Hopefully Sony make make a change to that in a firmware upgrade.

Duke Marsh November 6th, 2011 05:46 AM

Re: S Log Exposure/LUTs
 
If I recall the v1.3 firmware later this year will let you get S-Log out of A and a LUT out of B.

Leonard Levy November 6th, 2011 01:38 PM

Re: S Log Exposure/LUTs
 
How does the LUT affect zebras on the Flip out viewfinder?
If zebras incorporate the LUT then it should be useable for setting exposure as long as you understand what the LUT is doing and how much additional latitude you actually have in sLog.
I never look at histograms anyway.

Duke Marsh November 7th, 2011 07:23 AM

Re: S Log Exposure/LUTs
 
The zebra would have to go down to about 40 to be accurate on white skin, and it only goes down to 50.

Alister Chapman November 7th, 2011 07:33 AM

Re: S Log Exposure/LUTs
 
It wouldn't always go down that far. It will depend on your overall scene. A WFM or Histogram is more suited to S-Log exposure as this allows you to see your entire exposure range thus lets you choose how you expose. You don't want to always under expose. If your scene is a low key scene then you can afford to expose with higher levels than a high key scene. Under exposing and then lifting in post will increase noise which is normally undesirable.


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