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BenQ W7000 light spill - advice please

post #1 of 6
1/15/13 at 5:35pm
Thread Starter 
Hi,

I own a BenQ W7000 DLP projector. This is the first one I've owned and the last one I had any real experience with was LCD and was nearly 12 years ago so I'm not really sure if my unit has a problem or not...

Firstly, when there is nothing on the screen (as in "no-signal" black) the level of light hitting the screen is really high. There is a very distinct projection area which I'd describe as grey not black (with or without the dynamic iris mode).

Secondly, there is quite a lot of light spill out of the unit. I had expected there to be a certain amount coming from the vents etc. but I'm talking about a large fairly bright beam hitting the ceiling and coming from the lens. This unit is ceiling mounted and whilst the projection area ends up a few inches below ceiling height with no apparent spill above that on the projection surface, this extra patch of light it hitting the ceiling about 10-15" forward of the projector and is about 20-25" long (that is to say, projecting upwards at an angle towards the ceiling almost opposite to that of the bottom edge of the normal projected area).

The colour of this light is generally whiteish, but it does change with the image being shown by the projector (particularly blues I've noted).

With no image on screen of any sort, essentially what I'd expect to be complete blackness, the combined light from these two things is actually sufficient to see by in the room and it's impossible to achieve anywhere near a black image from the unit. This is with the lamp on economy mode - suffice to say that setting normal brightness increases these issues.

BenQ quote 50000:1 contrast ratio, I just don't see how that's possible with it behaving like this. (http://benq.co.uk/product/projector/w7000/specifications)

Is this normal? Should a projector at this level with that quoted contrast ratio be able produce a total illumination free black or is there always a background level of spill? Also, has anyone else experienced the ceiling spill?

There is also a faint spot of light when there is an all-black screen which never goes... I'm suspecting I have a dead "pixel" on the DLP here - has anyone else had this issue?

I'd be really grateful for any assistance.

Cheers!
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post #2 of 6
1/15/13 at 7:21pm
What image mode are you using? Have you tried your cinema modes?
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post #3 of 6
1/15/13 at 7:58pm
Thread Starter 
Hi there,

I've just gone through them all one by one in both eco and full brightness mode... no matter what I select the screen is always light. What I had not noticed before was that the top right corner of the screen seems to have a higher level of brightness/light spill than the rest of the screen. This also coincides with the spill which is hitting the ceiling, which is misshapen (not an even beam hitting the ceiling) to the right.

As I said before I'm really not familiar with how dark DLP projectors are with 0 brightness, but my gut feeling is there's some light shield/filter or something which is broken or not in place properly here - it just doesn't seem right.
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post #4 of 6
1/19/13 at 4:01pm
Thread Starter 
I was observing the issue a little more this evening and noted that the physical lens shift control does not affect the position of the light beam on the ceiling, so whatever is spilling out is outside of that part of the optical array. The brightness of this beam also does not change very much with the image brightness, also suggesting that it is coming largely straight from the lamp in some way...

Does anyone have any thoughts on this? I don't want to contact BenQ unnecessarily if it's just how it is and all that.
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post #5 of 6
1/19/13 at 8:52pm
Check out this post in the official Benq w7000 thread in the 3k+ forum:
How the Benq IRIS works

We documented how the IRIS works so you can lower the brightness properly if need be. The brightness and contrast controls should NOT be used to counter the projector being too bright. These controls are instead set with a Pluge Pattern (you can get a free Pluge from the AVS Rec709 Test Disk in this forum (Click here for instructions on how to burn the Rec 709 test disk to use in your Bluray Player - This Thread. If you do not feel like doing this at the moment, just leave them at 50/50 default settings, but don't adjust brightness and contrast just to attempt to darken the image.

The brightness control does not negate all brightness on the black floor, it is just lowering the black floor to a given point of crush, but it can only lower it so far. This is a very bright projector, and the ONLY proper option is to use the IRIS in the service menu to tone down the brightness. In the service menu, you can also control how aggressive the IRIS reacts to dark scenes by changing the MIN IRIS position while leaving Dynamic Black enabled. You can make the screen pitch black if you want, but I wouldn't recommend it necessarily as it would make the IRIS a bit bouncy.

On a new lamp, most smaller screens should be TOO LIT UP, and have too much light on it and look grayish (this is normal), but this totally depends on how bright you have it and how big of a screen you are using. The beauty of the Benq is that it has an IRIS setting we can fix this with. To adjust the IRIS in the service menu, go to the Information Menu, then press UP-Down-Up-Down-Up-Down and then the Enter button. Now be careful in the SERVICE MENU as you don't want to change something that might screw with the PJ. Go to the second menu from the right, you can change Current and Min Aperture Position to darken the overall image, but this will disable the Dynamic IRIS. If you leave Dynamic Black on and just lower Min Aperture setting, then it will make the dynamic IRIS more aggressive, but if you turn off Dynamic Black and lower the Min. Aperture position, then it will force the whites and blacks to stay darker (so the second option lowers complete light output, but the first option - leaving DB enabled only lowers the black floor in the method of how DARK the IRIS can go in dark scenes, rather than lowering white peaks).

As far as light leakage:

Hmm, look for sources of light leakage in the PJ itself, possibly coming out the side vents?
I didn't notice any light spill from my Benq, but I did not look carefully and as I have a black ceiling it would be harder to tell.
Edited by coderguy - 1/19/13 at 9:15pm
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post #6 of 6
1/20/13 at 9:09am
Thread Starter 
Thanks, that's really helpful - I'll take a look at the iris calibration when it gets dark enough smile.gif

As for the spill, I'm 100% certain that it is firing through the lens array and out of the front. If I use a disc of black card to block the output from the lens completely the spill disappears, with no obscuring of the vents. I did notice however when doing this that there is a second patch of spill even closer to the projector on the ceiling, and this is coming through the tiny gaps between the zoom and focus rings. This is significantly less bright and I'd not noticed it before as the other one engulfs it usually. That really doesn't seem like it should be?! Side vents are one thing but that's really bad design on what is not exactly the cheapest of projectors (albeit far from the most expensive of course!)
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