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Book Lights unnecessary for 4X4 frames w/ kinos? Diffusion voodoo?


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#1 David Vollrath

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Posted 23 April 2013 - 04:15 PM

Hey guys. Long time lurker, first time poster.

 

I've been working on my lighting skills for the past year or so and I feel like I'm getting a good feel for all the different ways I can soften and shape light. I'm mainly shooting smaller jobs and using a lot of 4X4 frames with 216 and pushing 1 or 2 4X4 kinos through them as a key light for medium closeups. In using this technique, I'm using less space than a booklight and I think I'm getting the exact same effect because the diffusion frame is glowing completely evenly. Is this the case? A lot of people have told me it's still not as soft, but I don't see how it matters if my diffusion frame is evenly lit? To me, a book light only becomes useful with larger frames or if you don't have kinos and need to soften a more specular head.


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#2 Phil Rhodes

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Posted 23 April 2013 - 04:27 PM

What you're saying makes complete sense to me. "Soft" really means "large", and If the diff is evenly illuminated across its entire surface area, it isn't getting any softer.


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#3 David Vollrath

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Posted 23 April 2013 - 06:49 PM

So now here's another question ... If you get a diffusion frame to glow evenly, does the type of diffusion matter? In other words ... does 216, Bleached Mus, Grid Cloth, and 1000h all provide the same effect as long as you've adjusted light output to make up for the difference in stop loss between the diffusions and ensure that you're filling the frame evenly? This is something I've been meaning to test for a while. I've seen tests like this before but they've all been useless to me because they don't modify anything else in the lighting setup when they switch out the diffusions.


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#4 Adrian Sierkowski

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Posted 23 April 2013 - 07:08 PM

Each diffusion is different. Also different is shooting through or bouncing off of it.

 

Someone on here, though I forget whom at present, actually did a wonderful test of the differing diffusion with the same lighting set up and same light. Some of them were subtle changes, others much more so. That is the valid way to test it; adjust for the stop only and you have just the effect of the diffusion.

 

Also, no a kino lighting a 4x4 is not the same as book light because how diffused something is is also based on the size of the luminary relative to the illuminated. Hence, a 4x4 would only be the same if it's side was relatively the same as, say an 8x8 further away, adjusting for other things.

 

You can make it "softer," e.g. the shadows which it creates become less and less defined (on a face for example) even if evenly lit by making it larger relative to what you're lighting (such as bringing it in closer) However, the characteristics of the falloff of said light then change (which is another usage for a book-light, further back.. it falls off more gradually.)


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#5 David Vollrath

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Posted 23 April 2013 - 07:34 PM

Adrian, I'm well aware of the size of a light in relation to the subject affecting how soft the light is. I'm also familiar with how falloff becomes more dramatic from a closer source. I'm not trying to compare an 8x8 book light to a 4x4 kino pushed through 216. I'm trying to compare a 4x4 book light with my 4X4 kino solution. I've seen a few DP's make 4X4 book lights when kinos were readily available and I always thought it was a waste of time. If you or anyone else can explain why a 4X4 book light is softer I'd love to hear it. Perhaps it's just something I need to see for myself.


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#6 Adrian Sierkowski

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Posted 23 April 2013 - 08:42 PM

Sorry then, misunderstood your query.

 

In such case 4x4 is 4x4. The kino, however, being a kino will have a differing look than a tungsten unit word. For myself, I avoid kinos and LEDs, and to a certain extend HMIs because I like to have a full spectrum source, and I personally find the slight warmth tungsten lights give me to be pleasing-- even before we get into diffusing them. And for myself, that's why I'd go with a tungsten book-light source over a kino (i typically use kinos in interviews and power sensitiveness situations or to match the floro look.)

It probably would look slightly different as well, all things equal on a 4x4 book kino -v- say HMI, but no one would probably notice unless there was a side-by side and even then, possibly not.


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#7 Brian Smokler

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Posted 24 April 2013 - 01:34 AM

Shane Hurlbut did a post on book light setups on his blog last year.  He discusses differing light sources, reflection/bounce panels, and diffusion materials.  Worth a look I think.

http://www.hurlbutvi...h-a-book-light/


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#8 David Mullen ASC

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Posted 24 April 2013 - 02:54 AM

Once you've filled a diffusion frame evenly it can't get any softer so there wouldn't be much difference at that point between the various materials other than some of them let a certain amount of specular light leak through, and some have a color cast. I'd only booklight a 4'x4' Kino if I had a bounce and diffuser that were larger than 4'x4', like a bounce into a 6'x6' white and then diffused with an 8'x8'. If you can't allow the soft light to spread into a larger surface then what's the point, you're just being inefficient with output, which of course may be another reason, you simply want to lose some output.
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#9 Guillaume Cottin

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Posted 24 April 2013 - 07:10 AM

I'd say there is a difference between a booklight and just shooting kinos through diffusion. It's not all about the size of the source relative to the subject: specularity, falloff and "spread" are also key concepts. I think booklights are very good at killing specularity, and, as previously said, reducing falloff. You can use a lighter diffusion on a booklight as the primary source is already bounced and less specular.

Depending on the diffusion you are using, booklights can give a very pleasing, natural look. I've seen them being used extensively on fashion/beauty shoots.

 

Booklights are especially useful for very large frames, at the condition that electrical power isn't an issue and when you have enough room to do it properly. This technique is also very useful for exteriors, as you can easily booklight the sun itself and get a much softer look than by just diffusing it (although in this case, double diffusing also works).

 

However, I would agree that, on a fast-paced set, setting up a booklight can be considered too time-consuming given the slight difference with other techniques. You mentioned Kinos; it's a good idea, I would shoot them through Depron in order to get a look that's closer to a booklight.

 

Now, depending on the surface you're bouncing the primary source into, it cas be more or less specular. I like to play with specularity. Controlled soft specular reflections can be really beautiful... But I already talked too much! I'm too young to reveal the tricks I had such a hard time discovering!!  :D  Forget what I just said!!


Edited by Guillaume Cottin, 24 April 2013 - 07:14 AM.

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#10 David Vollrath

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Posted 24 April 2013 - 09:45 AM

Once you've filled a diffusion frame evenly it can't get any softer so there wouldn't be much difference at that point between the various materials other than some of them let a certain amount of specular light leak through, and some have a color cast. I'd only booklight a 4'x4' Kino if I had a bounce and diffuser that were larger than 4'x4', like a bounce into a 6'x6' white and then diffused with an 8'x8'. If you can't allow the soft light to spread into a larger surface then what's the point, you're just being inefficient with output, which of course may be another reason, you simply want to lose some output.

 

Thanks David. I was hoping someone with your experience would say this. Makes me feel like I'm on the right track!

 

 

 

Shane Hurlbut did a post on book light setups on his blog last year.  He discusses differing light sources, reflection/bounce panels, and diffusion materials.  Worth a look I think.

http://www.hurlbutvi...h-a-book-light/

 

Yeah I saw that. I think it's a great introduction showing you all the options you have but it doesn't address at what point a book light can't get any softer.

 

I should probably do my own tests, but my current conclusion is that I should just be looking at different diffusions and really only be concerned with the density and not the material (unless I'm bouncing). That being said, I've been told 216 has a touch of a green cast to it, but I can barely see it.


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