What is REC709 (800%)

[Paul Anderegg]

Impossible to find any real information for this SHOOTING MODE....most links say it is a LUT for monitoring a separate video signal, but it is a gamma selection in every Sony camera I own.

Paul

[Cliff Totten]

Its just another gamma curve that tries to have a dynamic range expansion but still has a decent contrast. (Pre-dates HLG and tries to do what HLG does but less agressively)

You can think of SLog as being "rec709 (1300%)" but this only " rec709 (800%)".

[Christopher Young]

Alistair covers it pretty well, third of the way down the page:

Ultimate Guide for Cine EI on the Sony PXW-FS7 | XDCAM-USER.COM

"When viewing or monitoring via a LUT you should adjust your exposure so that the picture in the viewfinder looks correctly exposed. If the LUT is correctly exposed then The S-Log recording will also be correctly exposed. As a point of reference, middle grey for Rec-709 and the 709(800) LUT should be at, or close to 44% and white will be 90%. Skin tones and faces will be at the normal TV level of around 65-70%. As these levels are what we are used to seeing with a conventional video camera, this makes judging exposure easy.

This is really quite simple, generally speaking when using a Rec709 LUT, if it looks right in the viewfinder, it probably is right. However it is important to note that different LUT’s will have slightly different optimum exposure levels. For example the 709(800) LUT is designed to be a very close match to the 709 gamma curve used in the majority of monitors, so this particular LUT is really simple to use because if the picture looks normal on the monitor then your exposure will also be normal. The included 709(800) LUT is the most accurate LUT for exposure as this matches the gamma used in the majority of monitors. This LUT produces a nice contrasty image that is easy to focus. It is not meant to be pretty! It is a tool to help you get accurate exposure simply and easily.

Correct exposure of Middle Grey for the 709(800) MLUT. Middle Grey should be 44%. 90% white (a white piece of paper) will be 90% and skin tones will be around 65-70%.

Correct exposure of the 709(800) LUT using a 90% white card, white will be 90%. You can use zebras at 90% to check this level (remember zebras etc measure the LUT exposure level when LUT’s are turned on)."

Chris Young

[Paul Anderegg]

I think there is some confusion here...the term LUT is being used in place of or synonymous with GAMMA curve of a recording? My understanding of what you quotes was for a LUT applied to a video signal onto a monitor, such as Slog gamma with a REC708 800% LUT applied for exposure assist.

What am I missing here? I shot something with 800% the other night, and it was at 6db where my AGC said regular 709 was to be 30db...it makes a good super hypergain gamma :-)

Paul

[Christopher Young]

Paul my only experiences with 709 (800) have been with the FS7 so if you are using it with another type of camera I can't offer any advice. Sorry my man.

Chris Young