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Thread: Perceived brightness 12watt vs 3 watt

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    I would imagine that gas is still the ideal situation for beam quality versus any type of dpss or diode. I don't know enough about OPSL to know if that's the best of both worlds.

    Edisons comments regarding drivers is news to me. I hadn't heard the speed of a driver referred to before. How much of a compromise then is something like Badpips, Daves, Flexmod, etc. then, in terms of speed?? Are they better than "China", worst than, or, on par with? Are you saying that the same diode with a "faster" driver is going to appear brighter?

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    Quote Originally Posted by Bradfo69 View Post
    I would imagine that gas is still the ideal situation for beam quality versus any type of dpss or diode. I don't know enough about OPSL to know if that's the best of both worlds.

    Edisons comments regarding drivers is news to me. I hadn't heard the speed of a driver referred to before. How much of a compromise then is something like Badpips, Daves, Flexmod, etc. then, in terms of speed?? Are they better than "China", worst than, or, on par with? Are you saying that the same diode with a "faster" driver is going to appear brighter?
    OPSL are indeed the worthy successors of the old good gas lasers : comparable beam diameters, divergence, power and color choice. Comparable prices too

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    If You have a driver that has slow rise and fall times the laser responds slowly and is less on timewise. With fast rise and fall times and fast modulation the laser is more "on" then a slower driver so crappy driver that is slow makes the laser less bright. So yes its not all about divergence


    Interested in 6-12W RGB projectors with low divergence? Contact me by PM!

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    Quote Originally Posted by edison View Post
    If You have a driver that has slow rise and fall times the laser responds slowly and is less on timewise. With fast rise and fall times and fast modulation the laser is more "on" then a slower driver so crappy driver that is slow makes the laser less bright. So yes its not all about divergence
    Well this is true only for very short pulses, if you have a rise time of 1 or 10us, even 100us for a 10ms pulse it doesn't really add much more brightness

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    Quote Originally Posted by edison View Post
    There is no such thing as comparing 3 watt with 12 watt. If you have a 3 watt with 0.5mrd beam its has the same visible brightness as a 9 watt with 1mrd beam roughly. If you want to stay in budget, buy a chinese one in blue and drop in some quallity modules with Low mrd. It will be more expencive then buying 1 directly but you also have much more brightness and you have better graphics. You also don,t need so much power so its more save for the audience, you have better graphics and keep the brightness of a 12 watt. And yes we have 520nm green ;-)

    Its all about divergence.......
    I think you are mistaking here.

    I should be beam diameter instead of divergence.

    a 1 W laser with 1mm diameter will look much brighter compared to a 1W laser with a 10mm diameter, No matter of the divergence.

    When you measure a 1W with 1mm and 0,5 mRad to a 1W with 1 mm and 2 mRad there will be no difference (on short distance)

    But with a higher divergence laser the beam diameter will increaser much quicker on distance, so the brightness will go down due to the thicker beam diameter.


    To answer the question from the topic starter, I very often use my 1,5W RGB's together with my 4W RGB's. In smaller venues its hard to spot the difference.
    But when you are fighting agains LED walls the 4W are a better competition to the LED wall.

    Will the 12W have a WOW effect against the 3W, No, they only will be a bit brighter. If you planning to do small (lets say less than 1500 people) shows better invest in more 3 W projectors as 8 x 3W will have more WOW effect then 2 x 12W.

    But if you are planning to do big shows (with allot of conventional lights and ledwalls), or Festivals, definitely invest in +12W projectors is my opinion.

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    Please have look at one of my shows.

    the top 2 projectors are almost 3W
    the bottom 2 are 0,6W!
    so the top projectors got 5X the power

    Click image for larger version. 

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    Humm.... now you have me thinking about the whole 12 watt thing. Not that I'm talked out of it yet but... maybe the boat??




    Typically, I'm using about 5 - 2.5 watt RGB's (Pluto II's) in a room that's (for the rest of the world) 19.5 meters by 31.08 meters. Usually around 120 people but, as many as 400. I'm not fighting LED walls but often LED uplighting around the perimeter of the room. We also just built a 511.69 square meter outdoor patio that I may be using lasers on someday. Plus there is a possibility of other outdoor shows and larger venues so, naturally, I'm thinking more power - at least for a center projector perhaps.

    Granted, the Pluto's looked good at the Newton show after SELEM - as did the 2.5 watt green Mobolaser beam tables. But, dsli_jon's 9 watt Compact8 and flecom's 6 watt I think certainly outshined them.
    Last edited by Bradfo69; 11-11-2014 at 13:29.

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    I think you are mistaking here.

    I should be beam diameter instead of divergence.

    a 1 W laser with 1mm diameter will look much brighter compared to a 1W laser with a 10mm diameter, No matter of the divergence.

    When you measure a 1W with 1mm and 0,5 mRad to a 1W with 1 mm and 2 mRad there will be no difference (on short distance)

    But with a higher divergence laser the beam diameter will increaser much quicker on distance, so the brightness will go down due to the thicker beam diameter.


    To answer the question from the topic starter, I very often use my 1,5W RGB's together with my 4W RGB's. In smaller venues its hard to spot the difference.
    But when you are fighting agains LED walls the 4W are a better competition to the LED wall.

    Will the 12W have a WOW effect against the 3W, No, they only will be a bit brighter. If you planning to do small (lets say less than 1500 people) shows better invest in more 3 W projectors as 8 x 3W will have more WOW effect then 2 x 12W.

    But if you are planning to do big shows (with allot of conventional lights and ledwalls), or Festivals, definitely invest in +12W projectors is my opinion.

    Well diameter is also an important factor but since most projectors are 4-5mm beam i think that is more or less the same for most projectors at least at aperture. The divergence increases the diameter of the beam over a distance so no matter how you call it, beamdiameter or divergence will have quite an effect on the brightness.

    But this discussion should be held leaning against a bar with a beer in my hand that is served by Michel Rietveld

    Oh wait a minute there is a Lem coming!!!! Excellent!


    Interested in 6-12W RGB projectors with low divergence? Contact me by PM!

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    Quote Originally Posted by edison View Post
    so its more save for the audience
    I think I might have misunderstood you or you typed it wrong but working at lower powers because you have a smaller beam and a higher divergence doesn't mean its safer for an audience at all!
    Having a more concentrated beam means there is more energy density in a smaller surface area. Yes technically it could be safer in a sense that its easier to diverge a beam like this to make it safer but just calling it safer wouldn't be a good deal.

    I'd say it looks more appealing though for sure then watching a really fat beam used for graphics.. a lot of the details and space you want to use gets lost on the thickness of the beam and things will appear more fuzzy the higher the mrad.

    But yeah I think itsw hard to give you a definitive answer which one is brighter because it depends on the choice of optics and the quality of the overal module.. Personally I would also take in considiration how long the cheaper high power modules will last for you.

    For beamshow use the thickness of the beam seems to have an opposite effect then it has with graphics though..
    Due to the fatness of the beam it will appear more dense and fills the area more and seems to be percieved as brighter (though to me it seems a bit unlogical as the energy is less packed.. an american laser company told me this once where they actually increased the size of their beam diameter and not for safety reasons.
    Last edited by masterpj; 11-11-2014 at 13:55.

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    Someone asked about a formula.... Power density is really easy to understand if you think of the beam dimensions as an area. For example, if you have a rectangular beam from a multimode blue. At a given distance the beam is 5mm X 20mm. So, multiply them together to get the area 5X20=100 sqmm. Divide that into the power. Lets say 1W. 1W/ 100sqmm = 10mW per sqmm. If you double the divergence your beam will be approximately 10mmX 40mm. Now 1W / 400sqmm = 2.5mW per sqmm. 4X less power per area. This of coarse assumes the initial beam diameter is the same. However, because the difference in initial beam size is small compared to the far field size the ratio stays very close to 4X. The same can be seen for a round beam where A = pi*R^2.

    This clearly shows that for a spot on the wall the power density is very important for brightness. What is less clear is how power density affects the brightness in mid air. I don't believe its a 4x brightness ratio for mid-air. I wonder if anyone has the math for that?

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