Tightening the Light

[Traylen]

The circles allow you to duplicate your general zone lights as specials and give a multitude of specials anywhere on the front of the stage. It allows the light to stay tight no matter where the action is and to keep the stage focuses on whatever it should be focused on. The director realizes how effective this is, considering it actually takes less lights to do it this way if possible than to hang the zones and specials as seperates. The resulting look is amazing and allows the full splendor of the set to be shown and not be washed out by spill.

[ - Sorry in advance if my post sounds angry, it was not written in that tone. - ]

It''s exactly the same with shuttered light. Except the beam is not circular. There is no difference between a square and circle other then the shape. You focus it the same (ie whatever way you do at your theatre, no difference) but one is not round. It makes no difference, it's the same thing! What your saying in how you focus your lights is exactly how (atleast I think that's what you're saying) most standard light plots are done. I'm not saying change the way you aim the light and how to connect them. I'm saying shuttered light produces the SAME effect but with squares. You still get the nice wash, you still get the tightness, you still get the capabilities of specials. It's the same except it's a different shape. This method is deffinetely better in your case because you can't seem to get that tight look because your precious circles are too big. So in other words, if you shutter it down a bit, you get your tightness and the same "effect" of "amazingness" that you're talking about.

That's all I'm saying. I'm not saying squares are better, I'm trying to open up your eyes to see past the shape of the light. It doesn't matter, it won't effect it that much. But go ahead and do you circles I'm not trying to discourage you, I'm just trying to show you that it doesn't make a difference. Think outside of the circle (box).

Anywho, I don't think I'll say anything more on this matter. Because if this concept can't be grasped after 3 posts about it, then it will never be realized. If nothing I say can seem to show how these are the same thing then perhaps it's not worth my time. And I don't want you to waste your time in reading it either.

PS: Lights are round because of the lenses. If you tried to make a square lense you'd get barrel distortion and it would be much more inefective. Where-as shutters are added to help the designer take a light and make it fit to what they want.

 

[MSwan]

OK for those of you wondering about Altman field angles here is the manufacturer cut sheet:
http://www.altmanltg.com/Data/Detail/Theatrical Lighting/Ellipsoidals/360Q/360q.pdf
it gives you all the info you need to pick the right light for the job. ETC also has cut sheets for all thier units (they call them data sheets).

As to square light versus round(ish) light. Square light will work just as well to cover a stage with one glaring exception, efficency, if you are shuttering the unit way down you are throwing away light, if you have to push the shutter 3/4 of the way in on more than one side you are using the wrong light for the job. There is math that can be done to determine the correct light to use. The goal is to have a 10' area of light (square or round) at about 100 foot candles. I can say from past use that a 36° should be used from 15' - 20' you can cheat to about 30' before you lose too much light and you will have a 20' area at that point.

D = 2(T * tanA), D = diameter of field, T = throw distance, A = 1/2 field angle

Fc = Pc / D2, Fc = foot candles, Pc = Peak Candela, D = Distance

In the case of the original post in this thread it is obvious that the poster does not have the proper light for the job at hand, this is surely not his fault rather it is most likely the fault of a bean counter. Hopefully this info will help anyone else trying to figure out what lights to hang where.

 

[ship]

Well sated MSwan in above post. Though the Photometrics Handbook would be my choice for reference. My intent below is to deal with the lights on hand in assuming there is no other options for properly lensed fixture - this should be worked on and is perhaps a good use for at least some zooms in your inventory.

Size "A" or "B" gobos would given you can't borrow, rent or replace beam angles of fixtures have an effect on the image size.

I don't think top hatting or donuting a fixture will work well in it for the most part cleaning up the after spill of an image after it is already projected.

On the other hand, adding a drop in iris or having a fixture with an iris will cut down the image size without squaring it off as requested.

First you look into the image size of the gobo with a lot of actual sizes of pattern within the window. Than while still in the projection plane of the fixture, you supplement the size as needed.

As an after thought in having mentioned a gobo, if your intent is to still be round but cut down on the circular image, you can also add some form of donut into the same area that the pattern and shutters project from. This than would be round and of the same dia. If nothing else, some Gam Wrap type black foil added to the pattern holder to downsize the image.

Look to correcting it from the pattern area first, or at least second to changing the lens trains. Yes, your manual says that there is lens placement options for a lens train body. On the other hand, short of the right focal length lenses, changing their placement won't do much good.

 

[ship]

I don't know about conversion charts but I believe these are the conversions for the lights. I could be wrong, but I think it's pretty accurate.

6x4.5 = 50 degree
6x9 = 35 degree
6x12 = 26 degree
6x16 = 19 degree
6x22 = 10 degree

I don't know if there is an equivalent to a 5 degree, I doubt it though. I haven't seen or heard of any of the Altman 6x?? larger then 6x22.

Fairly close. This as published though I don't remember from where: (Probably Altman)

Fixture Lens Conversion Guide:
50° - 3.5Q5 / 360Q-4.5x6.5
40° - 3.5Q6 / 360Q-6x9
30° - 3.5Q8 / 360Q-6x12
20° - 3.5Q10 / 360Q-6x16
10° / 12° - 3.5Q12 / 360Q-6x22
5° - None



"are these more accurate?

4.5 x 6.5=45
6 x 9=37
6 x 12=27
6 x 16=17
6 x 22=9.5
8 x 8=20
8 x 10=16
8 x 16=6
_________________
Ross Zentner "
(Sounds like Rob is doing the actual math.)


In any case, average the tree for the most accurate or interchangable type of beam spread comparison. For lighting, the actual beam spread is more rough anyway. Note all three than base upon closest approximation.

 

[ship]

I'm not totally sure on why a round light is so important either, but I am told to do that and it does look good if you put them often enough across the front of the stage that someone can walk across and never lose the light. It also gives you unlimited zones that you can create out of those lights and the ability to use everyone of them as a special by themselves.

As for the lenses, a new lense tube is about $120 but new lenses to install in the current tube are only about $58, so that might be a solution.

You are talking about buying, what about renting just a lens train?

 

[disc2slick]

forgive me if this seems as a moronic solution, or if you have already tried this.

but freguently if you fuzz a beam out significntly it will have the same localized purpose (assuming it is a special) without getting that gross square look that has plagued you (and me, as a designer). so yeah, my advice play wth the "degree" barell, and the focus

 

[eamon]

Hi

Here is a jpeg of all beam angles and their sizes over the respective distances


enjoy

eamon

 

[Traylen]

I don't know about conversion charts but I believe these are the conversions for the lights. I could be wrong, but I think it's pretty accurate.

6x4.5 = 50 degree
6x9 = 35 degree
6x12 = 26 degree
6x16 = 19 degree
6x22 = 10 degree

I don't know if there is an equivalent to a 5 degree, I doubt it though. I haven't seen or heard of any of the Altman 6x?? larger then 6x22.

Fairly close. This as published though I don't remember from where: (Probably Altman)

Fixture Lens Conversion Guide:
50° - 3.5Q5 / 360Q-4.5x6.5
40° - 3.5Q6 / 360Q-6x9
30° - 3.5Q8 / 360Q-6x12
20° - 3.5Q10 / 360Q-6x16
10° / 12° - 3.5Q12 / 360Q-6x22
5° - None



"are these more accurate?

4.5 x 6.5=45
6 x 9=37
6 x 12=27
6 x 16=17
6 x 22=9.5
8 x 8=20
8 x 10=16
8 x 16=6
_________________
Ross Zentner "
(Sounds like Rob is doing the actual math.)


In any case, average the tree for the most accurate or interchangable type of beam spread comparison. For lighting, the actual beam spread is more rough anyway. Note all three than base upon closest approximation.

Ship, though your's is most likely more accurate, I was reffering to the ETC S4 ERS conversion, by which I meant the closest possbile ETC S4 to give the same effect or vise versa. The degrees that you provided are more like the degrees of the Shakespears, which would make sense since it's the same maker and they would want an easier conversion/comparison to their older lights. And yes, he was reffering to the actual math as we had previously discussed.

PS. 12°? I don't think I've ever heard of that lense size before. Is it much more rare then the 5 and 10s?

 

[eamon]

hi

oops here is the link proper

www.controlbooth.com/users/eamon


i think this is right


eamon

 

[ship]

Ship, though your's is most likely more accurate, I was reffering to the ETC S4 ERS conversion, by which I meant the closest possbile ETC S4 to give the same effect or vise versa. The degrees that you provided are more like the degrees of the Shakespears, which would make sense since it's the same maker and they would want an easier conversion/comparison to their older lights. And yes, he was reffering to the actual math as we had previously discussed.

PS. 12°? I don't think I've ever heard of that lense size before. Is it much more rare then the 5 and 10s?

I think that we are all most likely correct for the most part. Remember intent of what's published as compared to what even eamon chimes in (too long an upload for me to view but very accurate no doubt), has for comparison. ETC's intent no doubt was to publish what fixtures would reproduce the Altman line, same with in the Altman line what was most close in comparison.

Intent as no doubt that of with the importance of the question in general is as ETC states, as Altman states, as is calculated, what other replacement for one type of fixture you can use in most similar in beam angle can closest replace that of the known intended fixture angle.

One or a few versions is for the realistic beam angle of a specific focal length of a projectpr lens (old style), the other is what's closest to what is able to replace it in stating instead of projector lens status, the beam spread of the fixture. Given a change into what's presented as to beam type, is it any mystery that a 6x9 does not figure directly into a clear and cut beam spread of a more modern light? We here get into old time in crossing over to modern technology.

 

[Foxinabox10]

Has anyone ever tried buying new lenses and replacing them in S4's? If so, how did it go, experiences, suggestions?

 

[disc2slick]

Hey fox(inabox)

When necessity forced us to move our primary lighting positions in my high school, we had to order new lenses (we got ours from fourth phase in NJ, but you can def. find somewhere near you). What we got was entirely new barrels for the S4s we had so it was just a matter of swapping them out.

-dan

 

[Foxinabox10]

The barrels are twice as much as the lenses, so I was trying to just get new lenses if possible. Anyone? Also, does anyone know if the new lenses come with new degree labels?

 

[propmonkey]

the new lenses should have alteast a color dot on the edge if not the label on them, how else could you tell?

 

[Foxinabox10]

I'm talking about the degree labels that are on the outside of the lens barrel that tell you what degree fixture it is by looking at the fixture.

 

[propmonkey]

if not just color coded them. put a peice of colored tape on the barrel. a different color for each different degree, makes a good way to spot them from stage during a focus.

 

[zac850]

I'm talking about the degree labels that are on the outside of the lens barrel that tell you what degree fixture it is by looking at the fixture.

A black paint pen to cover the old label and a white paint pen to mark a new barrel is all you would require. I would be careful if you are going to buy the lenses and swap out the lenses in the barrels. While I don't know much about optics, it seems like you would have to be very careful to make sure everything is done perfectly so the beam still looks good when your done with the change.