How far should my MH light be away from plant ?

Hi all, here's my situation, I have had a few plants going for about 2 weeks now under just a few 26w CFLs. I was supposed to get my lights a week ago, but it took longer than expected.My plants look really good thankfully considering the less than optimal lighting conditions, but now I want to go ahead and throw them under the 400w MH. Is it going to hurt them to put them in such intense lighting since they are not used to it? If it won't hurt them, how far should the lights be from the plants? thanks for your help.

1.5 foot in between of your plant and light.

Thanks for the help. So will it be fine for me to go ahead and just put them under the 400w ? Or should I put the light further away and leave the CFLs on them and gradually move the MH a little closer each day then remove the CFLs when the MH is closer to them ?

Put your hand under it and get the light as close as you can without it burning. If it is too hot on your hands it is gonna burn your plant more than likely...

i think you should be ok, i put my 5 babys under a 600watter but kept the light far away(right at the top of the tent) then day by day moved it down putting my hand underneth the check heat, not 100% tho, sorry if thats no help lol

Thanks for the help everyone. I think I might just gradually move it down over the next few days just to be on the safe side.

That's the best way to do it. I always, start a couple of feet away, and ease my 400 watt MH down. Hardens them off, without shocking them or frying them.
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I usually start at around 28 inches with my 400w MH and then gradually move it down to around 10-12 inches or lower.

My reflector is air-coolable so I have a 6" 435cfm fan pulling the hot air out. I can probably get my light down to about 6-8 inches no problem.

Mine is about 15''. Get's a little toasty around 12''.