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Pinspots?


Karel Bata

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I need a really tight powerful but lightweight pinspot (rather like looking for the total DBO).

 

I'm looking at the American DJ Super Spot LED Lighting Pinspot 10W

 

http://media.cdn.adj.com/media/catalog/product/cache/1/thumbnail/800x800/9df78eab33525d08d6e5fb8d27136e95/s/u/superspotledleftjpg.jpg_17.jpg

 

Anyone used that? I'd like to know if it uses one large LED or a cluster. Shame there's no gel frame holder.

 

But that was released three years ago. Anything new that folks have spotted? Something with a really tight beam? And I don't really need the DMX capability.

 

Cheers! http://www.blue-room.org.uk/public/style_emoticons/default/wink.gif

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It looks good, but it has a soft edge?

  • Beam Angle: 6°
  • Field Angle: 12°

I can't find any videos or images.

 

I was tinkering with the Chauvet Pinspot 2 yesterday. With the 6 degree lens it has exactly the right characteristics for me - flat even spread with a sharp edge - but at 3W it's not quite bright enough. If I could only swap out the lamp...

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I may have a solution. To take the rear end of this Prolight 15W LED, and use the 6 degree lens assembly off the Chauvet pinspot 2. http://www.blue-room.org.uk/public/style_emoticons/default/laugh.gif That way I get a 15W, 6 degree lamp.

 

There may be thermal issues - the condenser lens in the Chauvet may not be able to handle 15W. I could try replacing it with one designed for more power (and why can I only source them from China? http://www.blue-room.org.uk/public/style_emoticons/default/sad.gif ). Could be a good idea to add an additonal heatsink and fan too. If it works I should get 1,500 lux at 5 metres while running only 15W.

 

I've tried using a 250mW red laser / chauvet combination, but though the light distribution was near perfect, the light output wasn't any improvement over the tiny lens that came with the laser. Upping the power of the laser will cause significant heat problems. So that looks like a dead end. (Unless I can find a way of water cooling the laser - water cooling in a light? http://www.blue-room.org.uk/public/style_emoticons/default/blink.gif )

 

Any thoughts? http://www.blue-room.org.uk/public/style_emoticons/default/biggrin.gif

 

 

 

Kevin, what size is the lens on the Stairville? Is it possible to change it? And how sharp is the edge?

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Different optics, the prolight uses a Total Internal Reflection, TIR lens close coupled to the LED.

 

Chauvet condenser some distance from LED.

 

Stairville micro groove fresnel lens spaced from LED.

 

Fresnel is going to be most tolerant of changing the source

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Yes, different optics, but at the heart of both is a small flat light source. You think it might work?

 

The Stairville lens may be mounted directly onto the PCB. Even if it's not there's likley to be a small condenser mounted directly on to the PCB which could prove tricky.

 

I can see other probs too: heat; and the chip's size - the 15W is likely to be bigger than a 3W and thus spoil the sharpness I like in the Chauvet.

 

Only one way to find out...

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Read up on "etendue", this describes the problem of getting a narrow sharp-edge beam out of a large source like an LED array.

 

Normally they use the LED to illuminate a small translucent dome or cone and use that as the "point source", however this wastes a lot of light. The TIR optic is much more efficient but you can't get a sharp edge.

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Kevin, what size is the lens on the Stairville? Is it possible to change it? And how sharp is the edge?

 

Physically it's about 4"/100mm diameter (I can measure tonight if you need a more accurate measurement), mounted at the front of the unit. As musht says, it's a plastic micro-groove fresnel lens. You don't get any other lenses with the unit, there's no user-change option that I know of.

 

The edge is well defined - not hard but not much spill outside of the main beam just a small fringe, i.e. beam angle and field angle are pretty similar.

 

HTH

 

Kevin

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Hi Tim. Yes etendue is a limiting factor in all lens systems, but the LED is tiny! Look at the sun - it is huge, but only sunbtends a small angle (a lens system doesn't care how far away a source is) so it's possible to easily create a reasonably sharp image of it. Unless I've misunderstood this...

 

The Chauvet works by having a metal plate behind the dome lens with a circular apeture. The lens system then focuses on this apeture - poorly, but rather well for our purposes. If you take the lens off and move it to a closer distance you will get an image of the chip. At the proper distance we get the sharp image of the aperture and the even beam spread which is the blurred image of the chip behind it. The upshot of this line of logic is that it doesn't matter how big the chip is - it's out of focus. No? Though you will get diminishing returns as it gets bigger.

 

Marrying the two systems (the two lights) may be too much of a challenge. Still it's all learning curves here and I have a month to get something that works. http://www.blue-room.org.uk/public/style_emoticons/default/wink.gif

 

 

Kevin, thanks. Hm.

 

You able to hold another lens element in front of the lamp and see what you get? Would have to be 4"+. Kind of depends on if you have one lying around. (My living room is currently strewn with stuff!)

 

They quote, at 2 degrees, 6,000 lux. Since 6 = 3 x 2, and 3 squared is is 9, then with light loss we could expect 10% - 600 lux at 6 degrees. That sounds good.

 

Oh, and how far away does the lens have to be to maintain a decent focus? If the result is not 6 degrees (unlikely) then at least we know it works in principle.

 

 

Cheers! http://www.blue-room.org.uk/public/style_emoticons/default/biggrin.gif

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