I need an opinion; Would a double ended 250Watt MH (like the one on DIYLabs.org) with a reflector and condenser lens be brighter than a 1000Watt MH without a reflector and lens? Does anyone know if the double ended 250Watt is nice and bright if done correctly? Thanks for any input.
dunno really, but I would have though the 1000W would generate FAR TOO MUCH HEAT. I stood in front of a 500W security light type fitting and it nearly fried my skin!!!! And I was about 1m from it. I think the 250W is the best. I think I'm gonna go for one of them in my OHP.
I'm gonna have to recommend strongly against a 1000 watt lamp. I have known people who have tried it and said that the heat was unmanageable (especially with a LCD that wasn't meant for projection). Another thing about the 1000 watt lamps is that their lighted center is too large to be considered a point source, which is absolutely necessary when building a DIY projector. Make sure that your light center is less than 80mm (the smaller the better). One more thing, you should get a lamp that is small in diameter (<2") so that you can use a small reflector and a condenser lens to gather as much light as possible. This isn't as easily done with larger lamps such as the 400 watt shop lights and especially the 1000 watt MH lamps.
Assuming that you use 1000W as point source (it isn't a good point source) without reflector and condencer and have 90 degree angle to fresnel you are actually using only 1/4 of it's ligh, that's equivalent to 250W. With 250W lamp and reflector and condencer lens you should actually be able to use about 3/4 of the light it produces, that's about 187.5W, and even without condencer about 1/2 of the light (125W), and with only 1/4 of the heat of a 1000W.
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