Dynamic Iris
11/25/2009 update to the Dynamic iris performance will be found further down in this section on the Iris. (It will be in bold italics.) I had suggested to BenQ, when I first reviewed the W6000, that they needed to improve the iris, and it's nice to know they took me seriously.
It is time to discuss the BenQ's dynamic iris (DI). From extensive viewing, the BenQ DI is not one of the smoother out there on today's projectors. True, it's better than some, but more than a few people will not be satisfied with the iris's action on some types of dark scenes.
For those of you not that familiar with my reviews, this is the type of detail that gets a lot of attention. I don't want to scare folks off. No projector with a dynamic iris is invisible in operation, all the time, and there are other issues (compression), that affect all projectors with dynamic irises. For those really wanting to explore all the trade-offs, this dynamic iris is a real factor, when it comes to determining how REALLY good the W6000 really is, compared to the competition, but it's just one item, and the iris performance certainly is not a disqualifier for most people.
Understand, you aren't going to see this all the time, I was casually watching about half of one movie before, all of a sudden, the iris action jumped out at me. At other times I spot it frequently in certain types of scenes. Either way, I'm not hunting for it, I'm just watching a movie. All projectors with dynamic irises have some issue. With the BenQ I'm making a particularly big thing about it, because I really couldn't find much else to complain about. (Ok black levels could also be improved, of course.)
I've been discussing with BenQ management, and they are discussing with the engineers in Taiwan. I have suggested they figure out how to smooth out the action with a firmware upgrade. If they do, they definitely have one of the premier projectors under $3500. If they go with the existing dynamic iris function, it will turn off a number of serious buyers, but most won't minde. Of course you can always turn it off, but I've also watched the W6000 doing just that, and the black levels are no match (as expected) for having it on. Further, at the W6000's price point, its blacks (with DI off) are not a match for the competition.
I've observed a lot of the same scenes with the BenQ and Epson side-by-side, and also side-by-sides with the BenQ vs. Sony. No doubt about it, both the Sony and Epson have much smoother iris action. In very dark scenes where the BenQ's iris tends to blatantly snap open, the other two projectors handle those scenes just fine by comparison, with the iris action barely detectable. The BenQ as noted isn't the worst out there, but everything else about this projector seems to be first class.
Here's how I can best describe what I'm seeing and objecting to. In the movie Hunt for Red October (I love that flick), there are pretty dark scenes where the sub (or subs) are sort of drifting or moving around slowly. In one case, part of the hull is almost a low medium brightness, and brighter than anything else on the screen. As that part of the sub is slowly moving closer to the camera - taking up more area, bang, all of a sudden, after maybe 5 or 6 seconds, the iris opens significantly, in a snap. You cant miss it if your eyes are open. It's as if, because of the very slow change in light level of the scene, the iris circuitry isn't willing to commit, until it realizes how much the scene has changed, and thinks "gotta catch up" and fixes things in one tiny fraction of a second. The other projectors seem to handle the same scene with apparently a number of smaller steps, but perhaps also longer ones so it almost seems to be slow steady change in the iris aperture, instead of all at once.
Update 11/25/2009: On those same submarine underwater scenes, and others where the change is slow and slight, the new BenQ firmware no longer waits and jumps as reported above. Rather, it's much smoother now. Every scene in Red October, Space Cowboys and those in Star Trek (Search for Spock), where the iris action annoyed me before, are now perfectly fine! I am very satisfied with the firmware upgrade, and that eliminates what has been, by far, my single largest performance complaint. -art
Upon close inspection the Epson and Sony iris action are also quite visible, it's just that they rarely make their action blatant, when you are just watching the content, not the projector. The BenQ's most noticeable is during a scene, while the Epson and Sony iris's are most likely visible right after scene changes. While I haven't done side by sides with the updated BenQ vs. these other projectors, I do believe that the BenQ's dynamic iris action is, overall, comparable to these others at this time.
Back to original review content: I don't recall the older BenQ's having quite so much an issue, so perhaps their new iris setup is trying to cover too much range. I think we are seeing that as a trend. The forthcoming new Epson Home Cinema 8100 claims a doubling of contrast from 18,000:1, to 36,000:1, and they are primarily attributing it to a new iris. I expect that the announced Mitsubishi HC6800, which exactly doubles the contrast of its predecessor (to 30,000:1), is also getting their better contrast with an improved iris that can close down further. It will be interesting to see if those, and other new projectors, will have more visible iris action than the models they replace.
I need to point this out - a doubling of contrast should provide a small, but recognizable improvement in black levels. Thus, you should see about the same improvement going from 2500:1 to 5000:1, as from 30,000:1 to 60,000:1.
To illustrate my point about an iris having more range, here are two pairs of images. Both are overexposed somewhat, so you can see the "blacks". Both are taken with different exposures to better illustrate my point. The first is just a black frame, from between scenes, and the second, seconds later, of bright white text on the black background.
The Epson projector is on the left, BenQ on the right. Allowing the irises to close down to maximum, note that the blacks on the Epson are much brighter. Add some brightness, and now the Epson has the blacker blacks. Relatively the Epson hasn't varied the light through the iris very much, compared to the BenQ where it's almost a night and day difference:
It certainly demonstrates how different two iris design can be.
