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Advice for background lighting


barefoot_dp
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Hi all,

Just looking for advice on what options there are for background lighting modifiers - particularly adding shapes like windows/blinds or streaks for emulating direct sunlight.

I know the "proper" method is to use cookies but that way seems like it would need a lot of flags? I don't really want to have to setup 4 extra C-stands to flag off the spill on all sides, so would much rather something that mounts on the front of a light (bowens mount). Has anyone used used any of the various projection lenses or can explain a bit better how they work? There doesn't seem to be too many of them available and those that are on the market seem to assume that whoever is looking for them knows exactly what they want, because nothing is giving me a good explanation of what I actually need!

What are the components I'd need to put in front of a bowens mount mono-light LED to get some nice hard-edged light streaks/patterns on a background from 10-20 feet away? And is there any way to do this without paying ~$500 for a lens projection kit?

Anybody able to offer their two cents?

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I suspect that even a Bowens mount COB LED is too soft a source for a modifier right in front of it to cut a sharp-edged shadow.

Short of using a really big cookie just off frame, I suspect the shadow will always be too soft because it's unfocused. Unless you can back it way up. The projector kits let you focus the shadow so distance is less of an issue. Some of the projection kits have chromatic abberation but that's the only way to approach this without going totally crazy imo. The Joleko type light is also SUPER useful because you can cut out a 4x4 piece of foamcore/bead board, angle it however you want on a c-stand or just tape it to the ceiling, and bounce a light into it, cut the edges using the blades in the projector, and use it as a soft light source (assuming no fog in the room). Of course with thin LED flex lights this isn't quite as unique as it once was.

Experiment with making a homemade cookie by cutting holes in an old cardboard box. Forget spill or whatever, just see how big it needs to be and at what distance to make shadows that are sharp enough. Maybe it's possible, not sure.

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If you do use a cookie, try to move it as far from the light as possible (without it being in frame) and having it be as large as possible. The light is probably sharper at full flood than full spot (if you're using a fresnel lens) and you can use black wrap around the light instead of a flag.... maybe.... I'd just get the projector. 😕 

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Could you post a reference image to help clarify what you want to achieve?

Best way to create fake sunlight is to use something like The Lightbridge reflectors - it’s all about creating the illusion of distance from the lightsource and making the beam parallel. 
 

This is a good explanation on the subject and a diy project if you’re into that kind of thing:

 

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These are the type of background effects I'm trying to acheive (although in my case talent would be lit separately - this is for use in interviews or explainers videos where I'm trying to get a bit more interest into an otherwise bland background). 

I wonder if mirrors would be a better solution than cookies? That way any spill would be going away from my background and would be easier to control.
 

light_1.jpg

light_2.jpg

light_3.jpg

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7 hours ago, HockeyFan12 said:

If you do use a cookie, try to move it as far from the light as possible (without it being in frame) and having it be as large as possible.

That's the bit I'm struggling with - the further the light is from the cookie, the more spill there is and the more flags are required. This isn't a problem if there's a grip truck on standby but there's a limit to how many c-stands I can take to a shoot as a one-man-band!

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42 minutes ago, barefoot_dp said:

That's the bit I'm struggling with - the further the light is from the cookie, the more spill there is and the more flags are required. This isn't a problem if there's a grip truck on standby but there's a limit to how many c-stands I can take to a shoot as a one-man-band!

If might look too DIY but I'd make a huge cookie out of cardboard, spray paint it black maybe, then bring it as close to the edge of frame and as far from the light as possible. You could probably fold it up for storage and straighten it out by weighting the bottom with spring clips. If the cookie is big enough and the cutout not too big you might be able to use the barn doors on the light to control spill rather than flags. The mirror approach can probably work well too. I always take the DIY approach but sometimes it doesn't look so good or work great, but worth trying on your own IMO to see.

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1 hour ago, barefoot_dp said:

I wonder if mirrors would be a better solution than cookies? That way any spill would be going away from my background and would be easier to control.

I would imagine that mirrors could be quite useful, depending on the geometry of your set of course.

The sharpness of a shadow is related to the ratio of cookie-to-surface distance with light-to-cookie-distance, if that makes sense.  ie, if you have a light and a wall, putting the cookie closer to the wall gives a sharper shadow, and putting the cookie touching the wall would give an infinitely sharp shadow.

Use of a mirror could mean using a light with a narrow beam to go the entire width of the set, hit the mirror / cookie (in either order) and then go into the FOV.  This would mean that you drastically increase the distance from the light to the cookie, even if the space isn't big enough to let you back up.  It does mean that the cookie would have to be bigger though.

Having said all that, it's pretty messy and wouldn't work if the there was haze and the path of the light went near the FOV.

It's also worth exploring how sharp you want the shadow to be.  Your example shots weren't all super sharp.

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Not sure if it's useful, but this video talks about getting hard shadows with a Nanlight Forza 500, which I think is the same type of light you're talking about?

 

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15 hours ago, HockeyFan12 said:

Some of the projection kits have chromatic abberation...

Yes.  Fringing can sometimes be an issue with some ellipsoidal fixtures.  Instruments that use lenses made for slide/film projectors usually exhibit minimal fringing.

 

7 hours ago, barefoot_dp said:

That's the bit I'm struggling with - the further the light is from the cookie, the more spill there is and the more flags are required.

Use an open-face tungsten or HMI source with a snoot.  Add a tube of blackwrap if the snoot is too short.  That should eliminate most of your spill, and the open-face filament/arc will give you sharp shadows if the fixture is set to full flood.

 

15 hours ago, HockeyFan12 said:

The light is probably sharper at full flood than full spot (if you're using a fresnel lens)

Both open-face and Fresnel fixtures always give their sharpest shadows on full flood.

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  • 2 weeks later...

Well I've done a tonne of research and I think I've actually come back full circle to the projection lens. I was previously leaning towards getting some barn-doors and using cookies/flags, but that still seemed like a lot of extra gear (and space) dedicated to reducing spill. 

I think I've figured out what that I need:

Godox SA-P Projection Attachment (which comes with an 85mm lens)
Godox SA-17 Adapter (which makes it fit on to a standard bowens mount)
Selection of Godox Gobos

This seems like it will do what I need, based on what reviews I could find, although I do wish it was available somewhere as a full kit rather than having to buy all the components individually - I just hope I'm not missing something.
 

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1 hour ago, barefoot_dp said:

Well I've done a tonne of research and I think I've actually come back full circle to the projection lens. I was previously leaning towards getting some barn-doors and using cookies/flags, but that still seemed like a lot of extra gear (and space) dedicated to reducing spill. 

I have a fair bit of experience creating patterns and slashes on backgrounds, and unless the desired pattern is complex, you might be better off just cutting what you need out of foamcor and just casting a shadow.  Slashes are easy to make with zero spill using bardoors and/or blackwrap.  With foamcor patterns the spill is not that big of a problem, if you are careful with your doors/snoot and if you leave a big border around the pattern.

If you really need to go with a projection fixture, consider a used Source 4 ellipsoidal.  They have a nice punch and go for as low as US$175 on Ebay (sometimes with the pattern holder included).  In addition, they take standard theatrical patterns -- there are zillions of them.  If you anticipate working mostly in close quarters, get the 36-degree lens (or the 50-degree lens).

 

 

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