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-   -   Finding correct exposure (https://www.dvinfo.net/forum/sony-xavc-pmw-f5-f55-cinealta/533698-finding-correct-exposure.html)

Amber Scott March 9th, 2017 02:25 AM

Finding correct exposure
 
Hi there,

I come from a news and 'run and gun' back ground where i was always taught that the best way to find exposure was to put your zebras to 70/75% and adjust so that they fell across some part of a caucasian face. Making further allowances for different skin tones.

I have read some people saying this is a terrible idea and is far too inaccurate, but often i don't fully understand their process that they advocate instead of the above.

As i move away from news to longer form and more high budget work i was hoping people might be able to offer a bit advice and create a discussion that might inform other!

Many Thanks in advance.

Amber

ps i put it in this thread as i am starting to shoot more with the f55 and f5 but if you feel it should be in another forum do just say! Thanks :)

Bill Ward March 11th, 2017 06:55 AM

Re: Finding correct exposure
 
Amber: there are as many different ways to meter exposure as there are camera operators. ;) And if you start using any of the various s-log choices, it gets even more complicated.

As you move up into the F5 and F55 world, you'll mostly need to experiment. But you are close to a good baseline. I also came out of the run and gun world, with zebras at 75%, and that's how I have my F3 set up for most shooting situations: 75% for zebra 1 and 100 for zebra 2.

For my camera/lenses set up and a controlled lighting situation, I find that if I take an average Caucasian face, open up until I see a few zebra 1 tinkles, then back it off until only one or two tiny zebras are left, I'm in a pretty good ballpark. Any more, and with my camera, the highlights on the faces can start to bloom just a bit.

But as you change cameras, you'll need to do some testing to see what works best for you and your post production setup.

Doug Jensen March 19th, 2017 09:22 AM

Re: Finding correct exposure
 
These are not questions that can be answered simply without more information. The "correct" exposure will vary depending on whether you are shooting CINE EI S-LOG . . . or with a scene file in the camera's Custom mode. And the even if you are using the Custom mode, the correct exposure level will still vary depending on your choice of Gamma and other paint menu choices.

But regardless of what you choose for those settings, you should never set exposure based on skin tone because not everyone has the same shade of skin. The differences in reflectance value of different people forces you to make judgment calls ( I call them guesses) about the person's race, skin color, etc. There's no point in using zebras if you don't know WHAT you are measuring. So if you want to use zebras correctly and have consistent exposures from shot to shot, person to person, etc. you should be judging exposure on bright, reflected whites and nothing else except possibly a genuine 18% gray card. But gray cards are hard to use in the real world. So looking at Zebra on bright, relected whites is fastest, easiest method and eliminates guessing in all but the most unusual shooting situations.

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