Originally Posted by safe bobo
Can anyone recommend which ND filter to buy off eBay for the w1070? Blacks are good of course, but I hear ppl say it can be better.
I do not have this projector yet but can give some general filter advice based on my experience with my Acer 5360. Your choices are limited to an ND2 (cuts light output in half) or ND4 (cuts light output to a quarter). The benefit of filtering will of course depend on your particular screen material and image size. A small reflective screen might warrant the ND4 while a large, less reflective screen may look better without any filter.
I bought both the ND2 & ND4 to allow comparison. The ND4 makes a huge improvement to absolute black level which on dark movies is noticably beneficial. Unfortunately brighter scenes and colors really take a kicking and look quite muted and drab. The ND2 seemed like a good compromise, somewhat improved black levels and reasonable colors and highlights. I happily ran with the compromise of an ND2 filter when my screen was 106" diagonal and close to a gain of 1.0. Since then I have switched to a 130" diagonal screen with a somewhat reduced gain (maybe 0.9 or 0.95). The ND2 filter does improve black level but doesn't leave me enough light for the new screen. I run without and whine about the blacks.
From what I understand the W1070 is even brighter then my Acer so you might find that ND4 is the way to go. On the other hand the BenQ also has better blacks to begin with so you might find the ND2 gets you where you want to be. For the few extra dollars I strongly suggest ordering both. Changing the lens is a pain so likely you will find one that you can live with and put the other in a drawer.
As far as the lens itself, both of mine are Hoya. I believe this is a reputable brand and I can see no distortions or obvious color shift when the filter is in place. One thing to be certain of before ordering is that the lens is glass. There are some plastic ones out there that will warp/melt with the heat.
For dimensions I just measured the diameter of the outer plastic lens ring...where ever you intend to mount it. I would be surprised if you find one that fits perfectly. Likely you will get one a few ml's too large then find a way to stick it in place. I tried tape but it fell off so ended up with a very thin layer of soft window sealing putty around the inner lip of the filter. Worked like a charm, but obviously is a pain to remove and install.
One last thought. If you intend on using the projector for 3D I think you will either have to devise a quick change setup for the filter or abandon the idea all together. 3D kills light output as it is so any additional filtering would be very detrimental.
Good luck. Hopefully someone who actually owns the projector can kick in some information for you as well.Edited by DavidK442 - 1/9/13 at 12:22pm