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Determining Scene Luminance Ratio... [Archive] - IndieTalk - Indie Film Forum




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Shot Renegade
02-27-2004, 03:00 PM
Hey, film geezers... I need a hand ;)

Ok, here's the mission:

On a high contrast scene determine the correct aperature to expose the scene with enough detail in the shadows whilst maintaining the textures in the highlights - ie on the lighter parts of the actors face.

The scene is a guy sitting at an office desk, he's got some backlight from the window behind giving him some rim light (got some 1/8th CTB for a bit of a moonlight effect), then a practical lamp on the desk etc... and it's all rigged with key's and fills but in a film noir style with enough blacks.

The situation is - I don't want to loose too much detail in the shadows so I need to know the luminance ratio to check if it's going to fit in to characteristic of my film stock. (kodak vision 200t)

Now how do I determine the scene luminance ratio... I know my incident readings for my key and fills but I need to make sure that I don't loose the darker areas of the picture off the toe!

Reflected meter readings are done from the position of the camera? right? But is this the best way to determine L.R.? Guys, give us a hand ;)

Radical! Cheers...

clive
02-28-2004, 09:12 AM
Sounds like an interesting exposure problem.

Working on the assumption that you need the face of the character exposed perfectly, I'd take spot meter readings on a mid grey card, to establish the right exposure for that area of light. I'd then do spot meter readings in the shadow areas in which I still needed detail and also in any hot spots to see how many stops difference there were between them and my mid-grey exposure.

If the exposure latitude was too wide, I'd mess around with different lighting configurations until I could get the spread I wanted.

Once I'd got an exposure setting that I was happy with, I'd also take a number of takes half a stop up and down from that position, giving me a spread of exposure to choose from.

scottspears
02-29-2004, 10:41 AM
16mm or 35mm? It makes a difference. You can push 35mm harder on underexposure. For 16mm, I'd say don't go any further than 1 1/2 stops under on the face and you can under 2 to 2 1/2 stops with 35mm.

Scott

Shot Renegade
02-29-2004, 04:22 PM
Sorry, yea it's 16mm... well super 16 - so same aspect as 35 but 16.

Shot Renegade
02-29-2004, 04:23 PM
Scott, with spot meter readings... how do you take them? I mean I've got a slight confusion as to where you take them from... I've seen people do spot meter readings on set and other people do spot meter readings from the position of the camera (like most textbooks tell you too)... what's what for what?

scottspears
03-01-2004, 01:05 PM
You spot meter anything and everything. Actually, I take 3-4 readings: highlights, brightest area (if not highlight), face or featureed object in shot and shadow area. I figure out what's most important, shadow detail or highlight detail and expose accordingly.

Scott

Shot Renegade
03-01-2004, 01:29 PM
So where do I take them from? Do I point the meter at the set whilst standing at the position of the camera... or do I stand on set and hold the meter about a foot away from the surface the light is hitting?