I happen to run w/
adjust-a-wings reflectors but the breakdown below can be applied to all spreaders. I started to post in another thread, but due to length and the potential for violence, I decided it best to start my own thread- a rare treat indeed. I haven't proofread but will make corrections on the fly, as usual. FYI I'm a 30 yr TV/mo pic cameraman vet. last position- Lighting Cameraman or Director of Photography, take your pick.
When I was eye balling the pictures of tinker toy and erector set knock-offs on the internet, the
adjust-a-wings stood out from the rest. I got lucky because I got what I figured I was getting. Took about 30 years to be able to know what I was getting off of an internet picture, though. Works great! for me and my style but there are a lot of styles and tastes out there so I/m tryin' to stay on technical and skirt either-or type comparisons.
I will tell you why, based on solid, easy to understand principles, most of my spreaders are in a box collecting dust. Guaranteed to make some of the spreader lovers cover their ears and bite back but who am I to stir up controversy, discuss applied lighting, physics for dummies, (ie me), let alone, dick around w/ op's paradigms?
Ahh...WTF? yuh~only go round once, in this epoch, (dimension?) anyways. So. Lets clear the room of adults, roll up our sleeves, and get down 2 it.
Hey! Teacha! Leave us kids alone.
And.....
Let's kick out the jams, MFs! :banana1sv6:
Blue Cheer?
Just goofin' on ya, (w/ the drama queen thing, that is). What can I say? I was an aspiring actor who got kicked back to the set and lighting design dept during my 1st semester in grad school.
The info I've gleaned while working w/ a-a-w spreaders can be applied to any spreader and it isn't earth shattering, either. Otherwise all of my spreaders would be collecting dust.
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The Down Low
There are applications for them. I'll use a spreader on a light that's dedicated to a single plant (or two) that's been lollipopped, and LSTd for a wide, shallow canopy and I'm sure there are other situations where a spreader could optimize the light.
Economics and redundancy are where the problem lies.
If I stood up at a IA 600 lighting workshop w/ an a-a-w reflector/spreader combo in hand and asked the crowd if the spreader would have an effect on lamp life expectancy, after an awkward moment while everyone turned to get a better look at the idiot who asked the question, the resounding answer would be, "Yes!"
Maybe not all would know the theory but who needs theory when you've had the unique experience of seeing/hearing/smelling and eating, (I've seen more than one gaffer picking glass out of his teeth after a lamp had gone off in his face), hundreds of lamps pop early as a result of having spent most of their lives in close proximity to screens, gobos, "cuc's", patterns, gels, cutters etc. Lamps for horticultural applications share the same laws and principles..
A lamp w/ a spreader tucked in next to it as it should be to optimize it's use, (will get to that, IAM), will have one area that receives a continuous kick (reflection) back at it- there's no way around it. The bend in the a-a-w spreader is the kick point. The same could be said of the reflector and, a reflector will, indeed, decrease lamp life but it does so in a gentler, wider, more diffuse manner.
The spreader kick focuses light and heat in a single line to the glass, the heat on the lamp surface is uneven, the lamp burns hotter than normal** due to the proximity, (ie** its specs), a stress point is created and poof! you've lost anywhere from one to four months of life from your lamp which would concur w/ my own experience w/ lamps and the a-a-w spreaders for the past 2 years.
To save some time and to keep it fresh for me, (I'm retreading ground covered in another thread), I'll do my own Q&A.
Rosebud: I've been using spreaders on my a-a-w rigs for years and I haven't noticed any difference in lamp life.
GG: Than they're either not mounted properly, ie too far away from glass or we are living in two universes w/ distinctly different physical laws. I can only address the first issue.
R: Do tell.
GG: The spreader was designed to be positioned 2-5mm away from the lamp- the closer to the lamp, the more enhanced the effect. Moving/bending the spreader farther away will save on lamp life but will also diminish the effectiveness of the application.
R: OK.So I lose a couple of months of bulb life. Big deal. The spreader will make that up for me by increasing the effectiveness of the lamps. I mean, I can almost drop the light right into the canopy. Great penetration.
GG: Do tell. (pregnant pause) OK. A spreader breaks up direct light from the source. Some of the light is thrown back at the spreader, some is thrown outside (ie below.) You can bring the light in closer but that isn't so much the result of having a wider spread. The light can be lowered because the spreader is blocking the direct shot that the light would normally throw out. That's the magic and main function of a spreader. It blocks direct light to keep the plant tips from frying at close distances. A Blocker or Blocker/Spreader would be a more accurate term.
R: Yeah, well isn't that exactly what it's supposed to do?
GG: It does what it's supposed to do, but it doesn't buy the additional penetration that some folks believe they are getting. A more dispersed pattern? Yes. A wider area of penetration? Yes, however w/ the caveat w/ the wider area of penetration comes less depth. If you want deep, don't block direct light w/ and object, even if it has holes in it.
R: But doesn't a light source that you can get right down in there compensate for the direct light loss? And how many foot candle are lost just to maintain a safe distance between light and plant top?
GG: Great question, and therein lies the Catch 22...well, almost. It's a trade-off, a borrow from Peter-pay Paul loop. You can block the direct light and re-disperse its luminosity, but realize that you're also losing efficiency because light loses transmission every time it hits a surface and is, a) absorbed, b)refracted or c) reflected. What you gain in distance by using a spreader, is essentially being lost in transmission. At best it's a wash.
R: And then there are the economic considerations- the cost of the spreaders and the increase in lamp expense.
GG: I'd add that intelligent energy use, resource management and environmental economics are underlying factors, and more important in the long run, as well.
