Conventional Fixtures Source Four (Ellipsoidal) and Barn Doors?

[Brentgi]

I'd like your input on this...

I'm going to preface this by letting you know that 90% of our conventional fixtures are Source Four ellipsoidals. We have a few pars, but we don't really rely on those.

Here's the scenario: We are house of worship that records the spoken word for distribution to other campuses/venues. Our media director is a brilliant guy with a great deal of video experience. He has a great eye and an big attention to detail. I've been working with him to try to eliminate some hotspots (caused mostly by mixing of fixtures, pars and S4s). We've come up with a plan to redesign our lighting so that we can get an even distribution across the center of the stage. Here's the catch-- we are worried about light washing out our main projector screen, which is on the back of the stage, mounted at about 5' from the floor. The stage is pretty deep, so it's not a huge deal. But we'd like to keep it to a minimum.

Now normally, I would just adjust the shutters to compensate. However, we are currently using diffusion gel in the fixture to help spread the light... so the shutters don't do what I really want. I've been asked about barn doors, which I think is a great idea, but I don't think that I can get barn doors for S4 ellipsoidals. Is this correct?

Another option... Soft focus the light, but even in this scenario the shutters will not do a hard cut.

Thoughts?

 

[seanandkate]

What might fit the bill is a half hat. (Tried to post a pic. Fail, but yea wiki!)

 

[Brentgi]

What might fit the bill is a half hat. (Tried to post a pic. Fail, but yea wiki!)

That's certainly a good thought. I'm not sure if that would do the trick. I'm basically looking to make a hard cut right beneath the projector screen.

 

[sk8rsdad]

If it has to be a hard cut on a single edge and neither the fixture nor the screen can be moved then consider cutting a piece of diffusion in half so the top portion of the beam hard focused.

 

[Brentgi]

If it has to be a hard cut on a single edge and neither the fixture nor the screen can be moved then consider cutting a piece of diffusion in half so the top portion of the beam hard focused.

Intriguing suggestion. I'm going to try this.

 

[sk8rsdad]

Silk may give you better control over the spill.

 

[Footer]

Or a flag of black wrap.... Cheap, easily adjustable, and it will stay forever.

 

[derekleffew]

... but I don't think that I can get barn doors for S4 ellipsoidals. Is this correct?

To my knowledge, no one makes a 6.25" barn door. The leafs wouldn't give a hard cut like on a Fresnel anyway. The half hat and half cut of diffusion are both good suggestions, separately or combined.

 

[WooferHound]

Don't use diffusion, Defocus the fixture
But you just said that you need a Hard Cut shutter ?

 

[JohnD]

To my knowledge, no one makes a 6.25" barn door.

Mr. Leffew, look what I found........
http://www.chauvetprofessional.com/products/ovation-f-6-25-barndoor/

 

[JChenault]

Echoing sc8tersdad. This sounds like a job for silk.

The issue is that diffusion will soften everything including the US shutter cut. Half hat or top hat will cut down on spill, but are not designed to shape the beam. I doubt if barn doors will give you a hard edge.

If you can't increase the number of fixtures so you can get rid of the diffusion, or add some side light, I would consider a silk diffusion. This will spread the light directionally so up you can still blend the lights side to side, burst still have a reasonably sharp US shutter cut,

 

[SteveB]

I'm only familiar with the Rosco and Lee products (sorry Keith), but the Roscolux 160 Light Tough Silk is the lightest linear diffusion I've seen.

Might just be light enough to still give you some L/R coverage as well as the US cut you need.

 

[lwinters630]

I'd like your input on this...

Now normally, I would just adjust the shutters to compensate. However, we are currently using diffusion gel in the fixture to help spread the light... so the shutters don't do what I really want. ........

Another option... Soft focus the light, but even in this scenario the shutters will not do a hard cut.

Thoughts?

Defusing a s4 is making it a soft edge fixture like a fresnel., shutter cuts and barn doors are less effective then. Besides soft focus, you may try peaking the field (vs flat) then overlapping fixtures 15%. You will still get good shutter cut.
Consider top, back, and side fills to keep good visual separation and dimension (form). This will also let you back off face light slightly reducing hot spots.

It is always a tough battle between live and video but it all starts with good lighting.

 

[Harrison Hohnholt]

City Theatrical makes barndoors for 6.25" S4's

http://www.citytheatrical.com/Products/barndoor?dept=36ad06a1-84a1-43c4-a654-cc6e4ee51140&subDept=

 

[jcslighting]

Are there enough fixtures to properly cover your stage?
Especially with S4 fixtures you should be able to get a fairly decent wash without hotspots if the overlaps are correct.
Why do you want a hard focused shutter cut vs. slightly softened? The bleed with them slightly softened is not crazy and they will blend much smoother that way.
Is the focus overlapped without side shutter cuts?
Can you use the PARs as down or back light to help blend things? Or even better, add a sidelight wash ?

To echo others, a barndoor won't give you a hard cut on an ellipsoidal - the barndoor or blackwrap will basically mimic the soft focus look.

 

[JonathanHarpur]

Snoots (tophats or halfhats) are worth a try, as are split cuts of diffusion. They're likely to be just as effective, and likely cheaper, than barn doors. I'd recommend at least mocking it up with the blackwrap first - though my guess is you'll likely be disappointed with the results, but trying it might save you unneeded expenses. I find a good deal of unwanted light on screens comes from bounce - either off the deck, set, or performers - from the fixtures, and there's not much you can do to eliminate that, unless everything is nice and black.

My suggestion, and it makes me itch to say it, is to look at getting a punchier projector, or if you have the budget, a video wall.

 

[dthomas32308]

What I have found is that if your have to use diffusion then cut the light with the shutter where it's just only about half of the spill from the shutter cut is spilling on the screen then the projector should be able to overcome the little bit that is on the screen. If you do the shuttering with you or the director sitting at the console with a preview monitor them you will be able to make the cuts look like a natural intentional dimming for the screen. The best advise would be buying a larger degree barrel so that you can get rid of the diffusion all together and have the hard cuts you desire but be warned hard cuts that are tight on the screen will end in making lamp changes more time consuming as you will have to refocus the fixtures every time because they will move while changing the lamp.

 

[SteveB]

but be warned hard cuts that are tight on the screen will end in making lamp changes more time consuming as you will have to refocus the fixtures every time because they will move while changing the lamp.

?. I've never had to refocus an S4 ellipsoidal just because I'm changing a lamp. Never had shutter cuts drift for this either. The only exception is when the unit is focused at or near straight down and you can't remove the lamp cap with the yoke in the way.

What am I not understanding.

 

[dthomas32308]

?. I've never had to refocus an S4 ellipsoidal just because I'm changing a lamp. Never had shutter cuts drift for this either. The only exception is when the unit is focused at or near straight down and you can't remove the lamp cap with the yoke in the way.

What am I not understanding.

The place I have issues with this has the front three front overhead electrics between 120-140' throw to the stage and at those distances the smallest movement from fighting to break loose a tight screw ends up moving the light quite a bit at those distances.

 

[sosayweall]

I would also recommend cleaning and bench focusing your fixtures so you get an even spread of light in the beam itself. Helps eliminate the need for diffusion to get an even wash. Of course silk is also the way to go.

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