Aspect Ratio
Where to start here. The HD72 is one of the first of a new breed of DLP projectors that use DLP chips that have 16:10 ratios, not the 16:9 which is the HDTV standard That gives you 1280x768 instead of the usual 1280x720 resolution. This has a number of implications:
It does mean that you can hook up a computer to your projector and output true XGA resolution, without any image degrading compression technology. (WXGA - "wide XGA" most often means1280x720, and therefore really can't do true XGA (1024x768) without compression. There are a small handful of WXGA projectors that use 1366x768 which can do XGA without compression. The later has only been available on LCD powered projectors. Texas Instruments (TI) has apparently decided that a good compromise is to stick to the 1280 width (same as the HDTV format) but add about 6% more height to the projected area giving them the 1280x768 WXGA). Yes that means there are now three different resolutions that are all called WXGA! (So much for standards).
So, do you buy a 16:10 screen (you can get those made custom), or go with the traditional 16:9 screen. I expect the vast majority will go with 16:9. That means that when you set up your projector to fill the 16:9 area, you will have some overshoot above and below the screen. If you have 100" diagonal screen, the usable surface is just shy of 50" tall. The overshoot at the top and bottom works out to a little more than 1.6 inches at the top and at the bottom. This normally means that the unused area (when watching DVD or movies will throw some dark gray light that will hit the mask around your projection screen. This should be barely detectable assuming your screen has a nice (typical) matte black border around the viewing surface. Note if you are buying a pull down screen (they normally have smaller borders, you might want to make sure it has at least 1.75" of black material at the bottom.
Of course, if you do go this route (a 16:9 screen), and you do project an XGA computer signal, you will have the first 24 pixels hitting the border at the top, and the bottom 24 pixels hitting the bottom border. If your projector is mounted (or placed) where you can access it, you could, of course zoom out just a touch to allow the whole XGA image to fill the screen.
I watched the HD72 on both my Firehawk (128") and the Carada Brilliant White (106"), and never noticed the light on the border, unless I was specifically looking for it.
Like most DLP home theater projectors, there are also some unused pixels on the left and right, so if you are trying to mount your projector exactly at the inner limit defined by the zoom lens, you may have a little space on each side of the screen. Optoma's lens throw info is further down this page.
Of course another big- for some, advantage of the Optoma using the 16:10 aspect ratio, is that this projector will double beautifully as a business projector. I guess that means a lot of people will be writing them off as a business expense.
Projector Lamp life
Optoma claims 3000 hours for their lamp (in Low Power mode), 2000 in Bright mode. Optoma tells me that with AI turned on, actual lamp life will fall between those two numbers). Most users will run the projector with AI on, which means the lamp will brighten and dim as needed. Let's guess at 2200 to 2500 hours?
Seating distance and Screen Door Effect
The Optoma HD72 projector is DLP, and as such has a pixel structure that is far less visible than found on most LCD projectors. As a result, for practical purposes, the Screen Door Effect (SDE) is not an issue. If you sit close enough to a large screen to actually pick up the SDE, you are probably sitting so close that the image is too soft to enjoy. The Optoma is comfortable at about 1 to 1.1 times screen width. with a 100" screen, you should have no issue with SDE if you are sitting just over 7 feet back. Most LCD projectors (which have much more visible projectors would require about 1.4x to 1.5x screen width). The one exception is Panasonic's PT-AE900u, which uses "Smooth Screen" technology, and has less visible pixels, but is also a touch softer than other projectors. (Personally I like the immersion of sitting close. I sit just about 11 feet from my 128" diagonal screen (10 feet 7 inches wide). That puts me between 1x and 1.1x. I can see the pixels in white areas like text credits of movies, but otherwise its not an issue.
In other words, if you like the big image feel, DLP projectors are for you!
Projector Lamp life
Optoma claims 3000 hours for their lamp (in Low Power mode), 2000 in Bright mode. Optoma tells me that with AI turned on, actual lamp life will fall between those two numbers). Most users will run the projector with AI on, which means the lamp will brighten and dim as needed. Let's guess at 2200 to 2500 hours?
Seating distance and Screen Door Effect
The Optoma HD72 projector is DLP, and as such has a pixel structure that is far less visible than found on most LCD projectors. As a result, for practical purposes, the Screen Door Effect (SDE) is not an issue. If you sit close enough to a large screen to actually pick up the SDE, you are probably sitting so close that the image is too soft to enjoy. The Optoma is comfortable at about 1 to 1.1 times screen width. with a 100" screen, you should have no issue with SDE if you are sitting just over 7 feet back. Most LCD projectors (which have much more visible projectors would require about 1.4x to 1.5x screen width). The one exception is Panasonic's PT-AE900u, which uses "Smooth Screen" technology, and has less visible pixels, but is also a touch softer than other projectors. (Personally I like the immersion of sitting close. I sit just about 11 feet from my 128" diagonal screen (10 feet 7 inches wide). That puts me between 1x and 1.1x. I can see the pixels in white areas like text credits of movies, but otherwise its not an issue.
In other words, if you like the big image feel, DLP projectors are for you!
