I kind of know what I need but I don't know what I need to achieve it...
Portable studio situation. Hundreds of small groups of folk (2 to 4 people).
I need a very soft vignette on the background. Constraint is that the light source (Bowens monobloc) has to sit over the heads of the subjects. Currently using a small reflector with barn doors. Difficulty is keeping the light from splashing onto the heads of the folk below - I have to get them to move forward so that they are in the shadow of the barn doors - there's a line on the floor but little margin for error. Subjects and light source are about 1,5m (5ft) from background. Light source at about 3m high.
A snoot just gives me a fairly hard circle of light. An angled background light - long edge downwards so no light splash - doesn't have the right shape,
I think I need some sort of snoot which can project a very soft oval of light about 2m wide from about 1.5m away and 3m off the ground with no light splash.
You can soften the edge transition from a snoot by mounting it without a reflector. There an Elinchrom snoot that works that way. I don’t know if there is a Bowens to Elinchrom adaptor. A grid on the snoot will also give you a nice graduation.
You can soften the edge transition on a snoot by cutting the edges into a large saw tooth pattern, or attaching black cinefoil in a similar pattern. Black craft paper may work. Or you could just fashion your own jagged edged snoot.
Lining a snoot with aluminium foil will also affect the light pattern produced by it. Even just a few inches near the exit will soften the edge. This would be the first thing to try.
If your working geometry is so rigid, lighting options are limited. Chopping a snoot and painting the interior white might serve: bigger circle of light but softer edge. Otherwise, you have the expensive route of projection spot with custom gobo.
I just thought there might be a totally obvious, off-the-shelf solution. But I guess solving lighting problems isn't like that! More like tin bashing and gaffer tape!
Osmium wrote:
...I need a very soft vignette on the background. Constraint is that the light source (Bowens monobloc) has to sit over the heads of the subjects.
Why does the light have to sit over the subjects' heads?
If you could put the light on a stand directly behind the center subject (hidden from view by the subject's body) it would simplify getting the shape you desire. It would also act as a physical limiter on where your subjects can stand, so they won't try to get too close to the background.
Thanks for trying to help BrianO, but if I didn't have the constraint I wouldn't have the issue to solve. It's a venue limitation (for good reason) - no stands, cables etc. in the floor space. Re: "so they won't try to get too close to the background" - ! Sorry but assuming that people will act in a way that we feel is logical just doesn't work - especially with the over excited folks at these events. Once they're on their marked spot for the photo it's fine - it's the process of entry and exit where folks can do very interesting things - like trying to walk backwards through the backdrop...
Osmium wrote:
...It's a venue limitation (for good reason) - no stands, cables etc. in the floor space.
That is a problem, then.
Best bet might be to try for even lighting, and use a painted vignette.
Osmium wrote:
...Re: "so they won't try to get too close to the background" - ! Sorry but assuming that people will act in a way that we feel is logical just doesn't work - especially with the over excited folks at these events.
Yep; that's why I like physical limiters/barriers, rather than just marks or even worse oral instruction only. It's the same reason concrete barriers do a better job controling vehicle traffic than painted marks on the roadway.
Try putting the background light down low on the floor with a grid or snoot and bounce it off the ceiling (or scrim) between subjects and background.
That's a trick I use because I have a very small home studio with low ceilings. It also works brilliantly as a "hair" light strategy for bald guys creating a soft rimlight glow like moonlight from behind rather than the sharp specular reflections normally seen (and desirable) for subjects with hair.
I missed that part about not being able to put anything on the floor space but the light could also be suspended overhead and bounced off the ceiling or scrim to diffuse it for the same net effect.
Yes - a grid could be an option - still have to fiddle to get the shape and it would need to be quite narrow. I'm using a grid on a softbox for the hairlight to good effect. I'm going to try butchering a couple of cheap snoots first since if I can get the characteristics right it would be a very easy setup.
Re Ceiling bounce - The "ceilings" are usually 20m to 30m away and of an "industrial" quality with large MH or Sodium(bleh) lights suspended from scaffolding.
Re Painted Vignette: Tried that. Hated the material. Size of the vignette is fixed and too broad. I now use "Diamond Cloth" to which I've added velcro loop fasteners around the edges. Can be scrunched up small for transport and presses really easily with a vertical steam iron.
! Sorry but assuming that people will act in a way that we feel is logical just doesn't work - especially with the over excited folks at these events. Once they're on their marked spot for the photo it's fine - it's the process of entry and exit where folks can do very interesting things - like trying to walk backwards through the backdrop...