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Old May 22nd, 2008, 01:38 AM   #1
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Lighting distance tests

Conducted with a single craftsman 500w work light and a frost white shower curtain slung between stands. Canon XL1s with zebras set to 85 f-stop set so zebras just appeared on the keylight side of the subject's (my) face. We did this test to try to figure out how to get rid of the "Hotspot" that happens so often in lower budget indie films. I just read somewhere that Hollywood favors larger lights farther from the subject and wanted to find out how much difference distance made. The shower curtain ends up as about a 6'x6' light once the light from the worklight is intercepted. No changes other than keylight. (The blue light on the left side of the face is from the monitor). Enjoy!

Full results at http://yafiunderground.com/index.php...ting_distances
Attached Thumbnails
Lighting distance tests-bare-4.jpg   Lighting distance tests-diff-10-2.jpg  

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Old May 22nd, 2008, 04:02 AM   #2
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You see that your diffusion flattened out the look of the lighting on your face, yes? If you want to keep the dramatic look of the undiffused examples, you'll have walk your curtain/light combo around to the side more. Also, the closer the diffusion source is to your face, the softer the light will be (you really notice this with the nose shadow). To maximize softness and efficiency, you'll want your light to fill the diffusion, but not go outside it. If it only fills part of the diffusion, you're not get the maximum softness you can given the shower curtain's size. Sometimes that's okay, if you just want to soften a little, but not lose too much of the light's output.

How far away from you is your curtain? If a soft source is too far away, it will essentially become a hard source again. The farther away you have to have it, the larger the diffusion needs to be.

Also the closer it is, the more dramatic the changes in exposure as a subject moves closer to/further from the light. For instance, if you have your 6x6 light 3 feet from the subject, moving 1 foot in either direction will probably make a pretty noticeable change in exposure. If that same light is 10 or 15 feet away, the exposure will look more even over that 1 foot shift. Of course, that light will also be a hell of a lot dimmer at that distance, so you'd need a more powerful source.

Another annoying thing about soft light is that it's much harder to control than hard light. Notice how in your hard light shot, the background is much darker than the diffusion example? So now you have to have flags or flag-like things to block the soft light from where you don't want it. With a hard source, you can simply use the barn doors (if you have them--though flags can make a harder edge, if that's desirable).

Welcome to soft light. To quote Peter Parker: "With soft light comes great responsibility".
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Old May 22nd, 2008, 07:35 AM   #3
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First image has bare worklight at 4' from subject, Second has the same 500w light at 10' with the diffusion screen at 2' (according to the slate).

We pointedly didn't flag any of the spill as we wanted to test just the effects of the distances of the lighting instruments.

I had one surprise in that the f-stop numbers to keep the exposure identical for each image changed with the placement of the diffusion screen. The light got more intense as we moved the screen closer to the subject. I expected the light's position to have that effect, but not the diffusion.

I love the inverse square law :)

BTW, we do have 16 more images of all the steps between these two images at the link above.
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Old May 22nd, 2008, 03:32 PM   #4
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You'll also find that not all diffusion is created equal. The thicker/more opaque the diffusion, the more it softens and spreads the light (and the more light it cuts out at a given distance).

Other diffusion materials that are commonplace, and easily available -

tracing paper
muslin

oh well. Can't think of others right now.
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Old May 23rd, 2008, 05:37 PM   #5
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Does anyone want to see any other tests like this done? I want to learn too, and as a geek, I have to tear these things apart to know them better and fully.

I do plan on doing fill distances, bounce distances, different light intensities, gel effects. I no longer manually white balance anything, I either use indoor or outdoor presets as in film, you'd select either indoor or outdoor film and then alter light color temperature with gels to fit to the image I want.
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Old May 23rd, 2008, 06:03 PM   #6
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Um, I wouldn't go through with that last bit. I use presets in situations where I can't accurately tell what I'm doing 'cause I don't have a production monitor with me (which, hopefully, is never a situation where you're using lights). When you have lights and a monitor, there's no reason not to do a manual white balance. YOu can always flip between the manual WB and your preset to see what looks better, but don't dismiss it entirely.

You want to balance to your key light/main light source, WITHOUT any gels on the lights, or coloring/warming filters on the camera. If you balance with either of those, you're negating their effect (white balancing with a warming filter on the cam removes the warming effect--ditto for lights). This is, of course, unless you're trying to trick the white balance for a certain artistic result (white balance through extra orange gel to cool off the overall look, through blue/on something blue to warm it up, etc.).

If your lights are a weird color temperature, then you won't always get ideal results with the preset anyway. But I would use your own judgement and a calibrated production monitor to see what looks best on each particular project, instead of arbitrarily deciding not to manually white balance ever again. I'm sure if film dudes could alter the color temp of a film stock, they would!

And if you do an ENG type work where you're in strange environments with not-quite-white lights, sometimes a manual white balance is the ONLY way to get an image that looks true to what your eye sees---when dealing with mixed color temps, for example. You just keep WBing on stuff until what you see in your EVF looks true to real life.
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Old May 24th, 2008, 01:02 AM   #7
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I specifically don't use custom white balance to attempt to improve my skillset for future work on films. I'm not saying it's a bad thing to do, but all the "Film Look" questions prompted me to assess what makes films look filmesque to me. So I began researching film stocks and found that "custom white balance" film stock doesn't exist... so I am now shooting the way film folks do in regard to color temperature.
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Old May 24th, 2008, 02:17 AM   #8
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I get your thinking, but it's not quite right, in my opinion. If you want to work in the film world, then do so--get a super8 camera, or whatever you can afford, and learn to work with film. If you're going to work digitally, you should learn to use those tools to get the best picture you can, which may sometimes include manual white balancing.

When pros shoot digitally with HD cameras, or even higher end SD cameras, they DO use presets (at least from what I"ve seen), but those presets are carefully calibrated with the many in-camera menus that higher end cams have. They're set up with a color chart and all that kinda good stuff. With the types of cams most of us have access to (I don't think you mentioned your cam in this thread), that's not possible. So while theirs presets are tweaked to be color accurate end everything, we're simply left with whatever Canon or Sony or Panasonic decided a 3200K or 5600K white balance should look like. Granted, with some cams you have custom presets you can apply along with a white balance preset, but it's not quite the same.

Also, the thing is, on a film set, they're generally not going to be using the craftsman lights and shower curtains. . .they'll have trucks full of Mole Richardson and Arri Lights, all that kinda stuff. The color temps of these consumer lamps are not always what they're supposed to be, where as on a pro light it should be pretty accurate. So if you learn to work with a preset white balance and Craftsman lights, you might work with a film camera for the first time and find that your Arri lights are much warmer/cooler than you were expecting, based on your experiences in video.

I guess I'm saying I don't think the methodology quite crosses over. . . they do have warming and cooling filters for film cams too. . .like I said, if they could white balance film stock, I'm sure they would.
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Old May 24th, 2008, 09:46 AM   #9
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f you want to work in the film world, then do so--get a super8 camera, or whatever you can afford
Can't afford it, bad economy, still unemployed after a year and a half with 10 years of experience (no-degree, no interviews).

I own a super8 camera, film is currently cost prohibitive. I can shoot 3 hours of video for the same price of just shooting 2.5 minutes of film. That doesn't include development and telecine so that I can edit it non-linearly.
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Old May 24th, 2008, 09:59 AM   #10
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Also, the thing is, on a film set, they're generally not going to be using the craftsman lights and shower curtains. . .they'll have trucks full of Mole Richardson and Arri Lights, all that kinda stuff.

I guess I'm saying I don't think the methodology quite crosses over. . . they do have warming and cooling filters for film cams too. . .like I said, if they could white balance film stock, I'm sure they would.
Techniques, not tools. We learn what we can, when and how we can. If I were to follow alot of the advice here, I'd have stopped making films years ago. Too many people saying "If you don't use professional tools, don't bother trying." That attitude upsets me. I'm not saying that this is your attitude... but everytime I mention no-budget solutions, someone has to bring up a lighting kit that I'd have to sell my camera to buy (I don't rent equipment due to the scheduling and staff I currently have access to - all of whom have complex day job schedules and family - moving to a market where there's more opportunity is not an option for me although I'd love to).

As for filters... I use filters for that, not white balance. I have a set amount of equipment that I bought when I was REALLY gainfully employed. Now that I'm not, I use what I own.
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Old May 24th, 2008, 10:54 AM   #11
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I use what I own.
Good on you Cole. If everyone used initiative as well as creativity, I'm sure there'd be less biased opinion. Unfortunately this is a trade where money rules - it's very expensive. Replies I usually get is "buy a new one" which isn't always an option for me either. At the end of the day, no matter how much money you have, it's no science to take a picture, which is essentially what we're doing. If you get acceptable results with home made and DIY lighting, great!

Just enjoy yourself, that's the main thing. I'm also a no-budget film maker who uses work lights, shower curtains, home made cranes, dolly's and anything else I can build, sometimes I am criticised for using a good camera but have home made equipment - main point is, as long as you are happy with what you have that's all that matters.

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Old May 25th, 2008, 01:33 PM   #12
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All the professional equipment gets you is more consistent color temperatures form fixture to fixture, more durability and more control over the light. These technologies all cam from some DP or Grip making something out of the materials on hand (except the consistent color temperatures which took highly skilled labfuls of scientists and technicians). I saw a picture of John Ford once shooting on a HUGE 35mm camera with his hat draped across the top of the lens working as a french flag.

Money buys you time. If you don't have money, work with what you have and spend the time instead. Time = Money. Given enough time, you can even fell your own trees to make your own lumber to work with on your builds.
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Old May 27th, 2008, 08:27 AM   #13
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"Money buys you time. If you don't have money, work with what you have and spend the time instead. Time = Money. Given enough time, you can even fell your own trees to make your own lumber to work with on your builds."

Couldnt agree more with you Cole. I read (on another cinematography website) some words which will stick with me for as long as im trying to get into this business. Essentially it went like this...

"you can have it done cheap, done well, or done quick... pick two."

anything can be done well if youre willing to invest either the time or the money... just depends which you have in more abundance i guess.
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