It depends on a couple things. I think the most important this isn't to look at the projector, but at the 3D glasses you're using. Each pair lets a certain percentage of light through them. So take that percetage to see how much light you should be getting. I think anything above 9 ftL behind the glasses is actually pretty bright. Another thing to look at is how bright (if it's actually brighter) is the 3D mode. Typically, 3D projectors will try and put out more light in the 3D mode. So if reading a review make sure to read how many lumens it's putting out in it's 3D mode.