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Blowing out the sun


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#1 John Young

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Posted 18 March 2011 - 07:19 PM

I may be crazy insane, but for some reason I KNOW we had a discussion on this very subject. Yet, no matter how much searching I do, I can't find anything.

So here is a question: How much light would be needed in order to have the subject lit properly, shooting directly into the sun, while having the sky, and sun mostly underexposed?

If I were shooting a still photo, I would throw on a ND filter and setup a few 1200Ws strobes on full burn. Couple that with f11 or 16, and you have a pretty cool effect. I can not find one example of this in motion picture. I only have marginal better luck in the still world.

I guess I could use a couple of those old school carbon-arcs! HA!
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#2 Adrian Sierkowski

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Posted 18 March 2011 - 08:10 PM

Not to sound too silly; but perhaps this would be much easier to do on a green screen.... Shoot the plate first and under-expose it as you'd like, then green screen talent in.
Or, if you want in camera, and it's a close enough shot, you can string up a lot of ND behind the talent.
Biggest problem is that by the time you have enough light you're basically blinding and burning your talent....
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#3 Ronald Gerald Smith

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Posted 18 March 2011 - 11:37 PM

I am not sure because I have never done this...

Maybe you can set up a net behind the subject to knock down the sun and the background? And then you can use bounce sources or lights to bring up the exposure on the subject?
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#4 Stuart Brereton

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Posted 19 March 2011 - 04:37 AM

Shooting in Bright sunlight, 24fps @ 100asa is going to give you a stop of around f22. To underexpose the sun by 1 - 2 stops, and still have your keylight properly exposed, you're looking at f32 -45. That means large HMIs at uncomfortable distances for actors, which may account for why you're having trouble finding examples!
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#5 John Young

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Posted 19 March 2011 - 08:06 AM

Shooting in Bright sunlight, 24fps @ 100asa is going to give you a stop of around f22. To underexpose the sun by 1 - 2 stops, and still have your keylight properly exposed, you're looking at f32 -45. That means large HMIs at uncomfortable distances for actors, which may account for why you're having trouble finding examples!


That is true, but the f/22 would be cut down by several Neutral Density filters.

I wonder if I could find a strobe that could blast full burn 12 times a second. Or four strobes six times a second. That way, as long as I have 24 strobe flashes per second, I could record the effect through all the ND and hopefully be around f/11. Of course, the talent is still going to have to ware some ND sunglasses.
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#6 Stuart Brereton

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Posted 19 March 2011 - 10:31 AM

Don't forget that cutting the level of the sun with ND is also going to cut your lights. It doesn't matter what stop you actually shoot at, your keylight still has to be brighter than the sunlight. It's more useful to talk in terms of illuminance than f-stops. Bright sunshine is about 10,000 footcandles, so whatever stock, ND or aperture you use, your lights must be putting out more than that. Now, according to Arri's photometric calc, an 18kw HMI fresnel puts out around 6000 fc at full spot, 30 feet from the subject, which leaves you 4000 fc short at least. For more output, you'd need something like an ArriSun 12kw, and they are NOT fun to stand in front of.
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#7 Ronald Gerald Smith

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Posted 19 March 2011 - 01:46 PM

Don't forget that cutting the level of the sun with ND is also going to cut your lights. It doesn't matter what stop you actually shoot at, your keylight still has to be brighter than the sunlight. It's more useful to talk in terms of illuminance than f-stops. Bright sunshine is about 10,000 footcandles, so whatever stock, ND or aperture you use, your lights must be putting out more than that. Now, according to Arri's photometric calc, an 18kw HMI fresnel puts out around 6000 fc at full spot, 30 feet from the subject, which leaves you 4000 fc short at least. For more output, you'd need something like an ArriSun 12kw, and they are NOT fun to stand in front of.


Talk about a sun burn....
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#8 Adrian Sierkowski

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Posted 19 March 2011 - 05:11 PM

are we talking sunshine, btw, or the sun proper, e.g. a ball in the sky?
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#9 John Young

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Posted 19 March 2011 - 07:19 PM

are we talking sunshine, btw, or the sun proper, e.g. a ball in the sky?


The gigantic main sequence star (G2V) that is about 1AU away from the shooting location.
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#10 Adrian Sierkowski

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Posted 19 March 2011 - 07:25 PM

Certainly something for green screen magic says me.
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#11 Jonathan Bowerbank

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Posted 21 March 2011 - 06:59 AM

Thought of mirrors/reflectors? Doesn't sound like you're planning on softening it much if you need the exposure, but it's worth experimenting with.
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#12 John Young

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Posted 21 March 2011 - 04:14 PM

I'm going to do a couple of tests. I don't like the idea of green screen magic myself, but such is the way of things now.
I'm still toying with the idea of syncing strobes with the camera.

I am thinking that a strobe capable of of flashing 24/sec. would be unimaginably expensive when you also take into account that more than one thousand watt/seconds is required.

So maybe if I get a whole bunch of those cheap novelty shop strobes, I can have them sync to the camera, and build the power needed from multiple units.

The second test I am thinking of scriming the entire background, and hope the mesh doesn't show up. Here are excellent examples of the style:

Posted Image

Posted Image

Misha Mikhaylov is a lovely photographer.
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#13 Tony Brown

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Posted 22 March 2011 - 03:14 PM

easy on stills but you'll fry person with enough hotlights. I briefly spoke to Unilux about the strobe thing a while back. they have a unit they developed for rollercoater pics they thought they might be able to adapt. In the end I got a bit bored trying to work out something you could more easily do in post.

If you PM me your email I'll forward you the info they gave me...
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