Originally Posted by dangc
This is certainly sounding a lot better for the 2D / D65 and I am feeling a lot better about the lumen level in the projector.
However, I am at a complete loss to understand why I seem to be the only one baffled by the lumens in 3D? Am I to understand this correctly, that when you put it in 3D mode the lumens drop in half to 450 lumens? It is in 3D that we need the extra lumens, and I could have swore that folks who have the projector notice a brighter picture in 3D mode (before putting the glasses on of course)? In fact I recall somewhere in this thread where they referred to it as torch mode? Can somebody explain why putting the projector in 3D mode reduces the lumens? Maybe amongst all the other discussions on this thread I missed this and in that case I apologize in advance.
This is simple:
When 3D is activated, the projector inserts longer dark times in the PWM of the D-ILA Pixels. This results in a brightness loss of 50% -> about 450 to 500 lumens
However, as a result, the glasses do not lose so much light anymore, just about 65%, because the open times of the shutters can be longer. So you end up with about 150-200 lumens.
Drawbacks: Much more picture noise because of the reduced PWM, less bit depth and 50% loss of native contrast.
The SXRDs work differently: Here they keep full brightness and contrast, but the glasses lose about 85% light. So you end up with about same brightness, but you do not have so much contrast loss as with D-ILA. And you do not have any noise at all.
I hope, this explains your questions...