brightness

[flotsam]

I have a question that I´m sure is probably answered somewhere,but I did look and couldn´t find.
can anybody guess the brightness of their DIY efforts?
how would a diy projector using a 3m 9850 with a msr575hr bulb compare with a commercialy produced 2000 lumin DLP/LCD projector ( in terms of brightness not the quality of the picture)?- I realise that there are loads of variables but please humour me.
thanks for any response

 

[wylie-c]

As far as I know, an LCD will only transmit about 10% of the light that hits it, maybe 15 at best. So if your OHP puts out say 4000 lumens, you would have 400-600 usable lumens coming out of it. A quick google search shows that yours has 11,000 peak lumens, so theoretically you should get at least 1100 lumens out of it.

 

[flotsam]

thats not too bright is it? Is there a way to produce a cheap set-up for beaming video image bright enough to compete with,say, 5 or 6000 lumin projectors- where high quality is low priority, using lcd panels?
thanks

 

[Quin]

If you were to use a ~40,000 lumen output 400w MH lamp you'd be getting closer to the target. There has been some talk of using 1kW bulbs, check for a thread on it 🙂

 

[wylie-c]

The only problem with using a 1kw MH, aside from heat, is that it would most likely wash out the colours pretty good. A desktop monitor was never designed to have that much light go through it. Commercial projectors use lower wattage lamps, like 120-200 watts. But the small size of the panels and the specially designed optics don't need anything brighter. In all reality, in a dark room, a 15" projector with a 400w HQI will be similar in perceived brightness to most commercial pj's. The only reason I can see to need 5-6000 lumens would be for projecting in a very bright environment or for a very large screen size, like 200" or more.