Exposure/hvx-200/noise/miami vice

[indybones]

Hi peeps....

Bit of a difficult one to categorize this question so may be in the wrong place...
And my apologies for the length of it.

Would very much like your help and opinion...

I recently read the August edition of American Cinematographer and was reading the Miami Vice section where Dion Beebe talks of photographing the film...

"On night exteriors, I tried to keep the exposure values at around 30 or 40 percent, never letting them fall below 20 percent, and kept gain at +3dB most of the time, rarely going to +6dB. It's tricky because you can look at the monitor and think the exposure looks great, and when you check the exposure values on the waveform, you find it's to low. When it's to low you get noise and often you cant see the noise on the monitors."

Couple of things really could some one please explain to me what he means by
"keeping the exposure values at around 30 or 40 percent " please.

Which got me thinking about exposure values and noise as Beebe has stated above.
I might be well off the mark with this one, was late at night when I should have been asleep...

But the HVX-200 has had lots of comments on the amount of noise it produces when it's struggling for light. As I was experimenting with the pedestal increasing and decreasing it I saw on the view finder/LCD screen that when the pedestal was in the - values you could literaly see the noise flickering alot more harshly then when it was in the + values.

So I was experimenting with a few cheapo lights yesterday, the first one was just a 60watt daylight temp, used as key at a side angle this produced a nice outline to the one side of my face, then threw the rest into dark shadow, just with this setup I couldn't really see any noise.

Then I used a 500 watt and the 60, what happened was that there was more exposure, more mid tones (because there was more light) but with this came a lot more noise and significantly a lot more blocking.

So (off the top of my head) say if we had a scale where
0= pure black and 7= pure white
and I was exposing for a face which would be about 4-5 ish, the highlights hitting at around 7 would still be in range, but the shadow levels from 0-3 would be struggling and would become noisy/blocky. So would it be advantage to increase the pedestal slightly so that there is more detail in the blacks and so that the camera wouldn't be struggling, and so that there would be less noise????


Jeeez I've just re read that sorry for the length hope all that makes sens...

And thank you for any buddha style enlightenmnet you can offer me.

Thank you

Indy

 

[Ryan Patrick O'Hara]

I am not sure how the HVX processes signals specifically. What I do know is that slight over exposure (so long as your highlights don't suffer) and bringing the image down in post can help the noise issue.

Regarding the percentages, have you used the marker setting on the HVX200? 0-100% is referring to the exposure. Over 100% = absolutely no detail in highlights, as under 7% area ='s almost 0 detail in the shadows. But don't expect 99% to have detail. That just means there might be something.... like a couple of pixels detail.

Also, I don't know if you are aware, but the newest HVX200a has a very clean signal which blows the old HVX out of the water. I just shot a USC grad student film two weekends ago with it. I had the gain up to +3 and it looked better then the normal HVX at 0+.

Speaking of Beebe... Not sure when I read this but when talking about gain, he said that you would be surprised how much the audience would let you get away with, so long as you keep the faces clean.

He would mask out the faces and raise the gain of the rest of the scene. As long as there was not too much noise on the faces, the audience did not seem to notice as much as if there had been.

Interesting view from the king of digital bigscreen noise. lol.

 

[indybones]

Thank you Patrick...:thumbup:

'What I do know is that slight over exposure (so long as your highlights don't suffer) and bringing the image down in post can help the noise issue.'

Nice I'll give that a go....

'Regarding the percentages, have you used the marker setting on the HVX200? 0-100% is referring to the exposure. Over 100% = absolutely no detail in highlights, as under 7% area ='s almost 0 detail in the shadows. But don't expect 99% to have detail. That just means there might be something.... like a couple of pixels detail. '

Nope I didn't know about the Marker I have been using the zebra thats all....

Do you know how Beebe would mask off the faces?...In camera?


Thank you for your help Patrick...

Indy

 

[Ryan Patrick O'Hara]

That process I described was from Collateral,

"To pull in the night time environment outside the cab, we always had the cameras wide open, with the gain at +6dB," explains Beebe. The resultant image was extremely overexposed, says Cameron, "to the point that it was a little freaky." To remedy the situation, the footage was then brought to colorist Stefan Sonnenfeld at Company 3 in Los Angeles, who, using Power Windows [sometimes as many as 10 or 12] on a digital intermediate, brought the levels of the faces back down to an acceptable level, leaving natural looking faces surrounded by the L.A. nightscape.

For those who may not know, 'Power Windows' are tools a colorist uses to only manipulate a specific part of the frame.

 

[indybones]

Thanks patrick....:thumbup:

'Power windows', is there a way of being able to do something similar in FCP, because that could be a real life saver for correcting exposure etc?

I have used a technique where you double up the clip onto the above timeline, then make a 4 point garbage matt, place that at a certain point then boost or cut the exposure, however it's not the best and render takes ages...


Thank you

Indy

 

[Ryan Patrick O'Hara]

FCP has a program called "Color" which is absolutely amazing. You can make VERY easy power windows, custom shape power windows, animate the power windows to move, and even use tracking points to move the power window with an object effortlessly.

Amazing stuff.