lumens vs Watts?

[dream]

EDIT: The way some of the members here have desperately tried to identify my location and nationality for whatever reason they believed was needed for by asking an admin to check my profile logs and researching me by the content of my posts has been very creepy and unnecessary. So bye.

[swamidog]

lumens are a little complicated because you have to take into account the visibility factor of the different wavelengths in your laser projector.

measuring in mW removes that necessity.

Okay, so I understand the huge differences between video projectors and laser projectors and they can't replace one another.
I'm just curious.

Video projector's brightness is usually mentioned in lumens (like 3000 lumens).

Laser projector brightness is usually mentioned in (mili)Watts (like 800mW).

Let's assume you convert an ILDA animation to an avi file, adding the "blurriness effect" you would get when projecting with a laser projector), then play the video with a regular video projector and the ILDA file with a laser projector, "side by side".

How much brighter would the laser projection look compared to the video projection? I understand, vague question, vague answer. And I didn't mention how bright the video projector would be in lumens and how many mW would the laser one have. Think of a medium power video projector (power determined by lumens) vs medium powered laser projector (power determined by miliWats). You can use your own values and compare them.

[absolom7691]

Not to mention, LUX. LUX is how bright your image will be based on the brightness of the lamp source (lumens), the distance your screen is from the projector, the size of the projected image. There is a lot more to it. A 2500 lumen projector would be extremely bright, 1 ft away from the projector and with an image size of 1inch^2. It would be "dim" at 30 feet with a projected size of 10feet^2. I don't think you can really translate these two.

[absolom7691]

So... is it technically possible that a video projector can be brighter than a 1W laser projector?

Well, yes but you have to take into account that the further away the projector is and the wider the image is, your light source is going to need to be exponentially brighter. In the real world, you are not going to get a projector to be as bright as a 1W laser projector unless your lamp source is in the 10s of thousand of lumens. Even then, you're not going to be able to project very far before the brightness falls off quickly. Realistically, this is not a realistic expectation. Besides, by the time you get a video projector that bright, you will exceed the cost of a laser projector by A LOT e.g. http://www.ebay.com/ctg/Barco-XLM-HD...ctor-/66750185

[planters]

Here is a description that I like. The lumen/watt for 507nm light to which the eye is most sensitive is 1700 and for balanced white 555nm light(sun light is 670).

http://hyperphysics.phy-astr.gsu.edu...on/bright.html

The presumption is that the video projector needs to produce white light. I have a 4,500 lumen video projector (Acer) that looks close to a 1W RGB laser projector when both are producing a similar graphics show.

[m0f]

The fact that one is vector scanned and the other raster scanned adds to the difficulty in comparing the two for brightness. There are of course some blanked lines with vector scanning, in general I would think a much greater ratio of it's scan time would be spent scanning the image vs a raster scanned projector which for similar artwork would spend a great portion of it's time blanked.

I have a 4,500 lumen video projector (Acer) that looks close to a 1W RGB laser projector when both are producing a similar graphics show.

How does that translate to beam shows ? Have you tried adding a bit of fog ? I wonder if it's possible to get some decent beams out of a video projector with emulaser or similar ?

[The_Doctor]

Yes, because the divergence of a video projector is much greater than that of a laser beam. While scan angle will diverge the way a video projector does, the beam's divergence is much smaller and doesn't scale up with it.

This is similar to thin single-mode diode beams looking brighter for the same power as a fatter beam. High energy density in a small region is what makes us see it as bright. The amount of light that reaches us from the star Sirius is extremely small compared to daylight sky, but Sirius is often visible in daytime because the almost point-like source has greater energy density. Even spread thinly after travelling several lightyears, it is still brighter than a similar point-like bit of daylight sky.

[planters]

There have been a couple of threads on the use of video projectors used to complement laser projectors in a show. I started some of these when after a presentation by William Benner of Pangolin explained that Beyond permitted a video projector to be treated as one of the laser projector channels in a multiple projector show. He was right and his primary reason is that this allowed legal audience scanning with this projector because it was non-coherent and less intense, as explained above.

I was intrigued with the enormous bandwidth of the DLP (and of course LCD as well) controlled projectors. They are something like 100,000 KPPS. They can produce a point of light that is equal to a 1/2 mrad divergence RGB projector because the display lens is so large ie 75mm in diameter. But, this point is much less bright and so legal and safe. These do work well when used to complement a laser projector for high content shows, but will appear dim if used with much more than a 1W balanced laser.

[norty303]

Do you mean there are some consumer video projectors, that is, cheaper than 5000$, that can basically replace 1W laser projectors and even do more? I've seen some chinese 4500 lumen projectors in the 2000$ price range. They are a bit expensiver than chinese RGB 1W laser projectors with 40 kpps scanning, but not that much, and Kvant and other non-chinese laser projectors are even expensiver.

Check out used projectors such as the Sanyo PLC-XP series (100L, 200, 45, 50, etc) also rebranded as other brands depending on country.
You can get >4500 lumens for under £1000/$1500

Longer throw lenses will make them brighter over distance but reduce your 'scan angle'. Trade offs in every medium.


But I think trying to compare some of the specifications of lasers vs video projectors is pointless as they are simply very different things that can be made to give a similar effect, albeit achieved very differently.

[polishedball]

There have been a couple of threads on the use of video projectors used to complement laser projectors in a show. I started some of these when after a presentation by William Benner of Pangolin explained that Beyond permitted a video projector to be treated as one of the laser projector channels in a multiple projector show. He was right and his primary reason is that this allowed legal audience scanning with this projector because it was non-coherent and less intense, as explained above.

I was intrigued with the enormous bandwidth of the DLP (and of course LCD as well) controlled projectors. They are something like 100,000 KPPS. They can produce a point of light that is equal to a 1/2 mrad divergence RGB projector because the display lens is so large ie 75mm in diameter. But, this point is much less bright and so legal and safe. These do work well when used to complement a laser projector for high content shows, but will appear dim if used with much more than a 1W balanced laser.

Was someone making a hardware box to convert ILDA to video? I vaguely remembering sending them an email and not getting a response