HDMI or DVI Input
As long as we're out back looking at the input panel, let's talk briefly about HDMI. Some of the projectors we looked at in this report do not offer HDMI or DVI inputs. That means no pure digital abilities. The future is digital (how "last year" is that line?) But, in a K-12 environment, there are considerations. First, projectors sporting HDMI are probably $50 to $100 more than a similar model without, when such a comparison exists. Secondly, HDMI cabling is expensive, and it can be flaky at long lengths. Still there are high quality cables, and there are extender systems good for hundreds of feet, even 1000+, if needed. (Most extenders take the signal, convert it, and send it out over CAT5 or CAT6 networking cable, and convert back at the projector end.)
If you should be working at the school district level, then certainly considering HDMI / DVI - digital should have been part of previous considerations. I don't know what percentage of schools or districts are now going digital, but it has to be growing. It would be very foolish for any AV or IT manager responsible for projectors (and computers?), to not review each year, what type of digital strategy makes sense, and when (if ever) to start integrating projectors digitally.
I'm not saying all schools and districts should be digital, or should be in 5 years. There are any number of considerations in terms of bandwidth, type of content, future compatibility, that must come into play. The point is, digital is becoming more common (if still a small percentage) in the classrooms. The free advice (we know what that's worth): Stay on top of it.
We're pleased that, this year 11 of the 15 projectors in this report do offer HDMI or DVI connectors and compatibility. Note, none offer HDMI 1.4a which is essentially necessary for Blu-ray 3D. Remember, most likely any projectors you are buying today, will likely be asked to last about a decade, and unless school budgets start improving again, perhaps a whole lot longer.
So, implementing digital for projectors is an issue of long term strategy and cost containment. That means for some schools and districts, it may even make sense to start converting to digital sooner, rather than later. And that may mean starting to implement digital for projectors soon, even if other digital parts to the overall computer strategy may still be a couple of years from implementation.
USB can replace your analog VGA port, or HDMI. DisplayLink is starting to gain popularity. Instead of using vga cables, or HDMI to feed content to the projector, some projectors are now using the DisplayLink protocol to replace those older methods. What that means is that if your projector supports DisplayLink and so does your computer, USB can now be used to handle the display. For that matter, it can also drive your regular monitor as well.
I don't have any pulse on the how popular DisplayLink will come, but it is another area who's use is growing. At the end of 2010 DisplayLink supposed to be upgraded, to 3.0 with far more (up to five times I believe), throughput. I cannot report on that however, and we did not work with the DisplayLink in most of the reviews, favoring HDMI or the traditional analog computer input.
DisplayLink can support multiple displays at one time, that's just downright handy for feeding a desktop monitor and a projector, at the same time.
Well, brightness is hardly a "special" feature, but it is a key one for most decisionmakers choosing projectors. Back in 2000, the popular, large, "rental and staging" projectors - used for meetings in hotel ballrooms, small auditoriums, and large multi-purpose rooms, were typically about 50 or more pounds, and output a "blinding" 2000 lumens. Today most entry level projectors put out at least 1500 lumens in 4 and 6 pound boxes. Most of the projectors in this report are 2500 - 3500 lumens, and well under 10 pounds. We used to say, 2000 lumens is fine for a presentation to 250-400 people. Of course we assummed a nearly fully darkened room.
From a practical standpoint, 2000 lumens in a classroom-sized environment can handle pretty much anything but sunlight hitting the screen. Screen sizes in classrooms tend to stay fairly small - from 60 inch diagonal to 80 inch diagonal. On those sized screens, a solid 2000 lumen projector should be able to do a respectable job even with full fluorescent lighting on. OK, if the lights are only a foot or two in front of the screen, it might wash out a bit, but the point is, today's entry level projectors have plenty of horsepower for the classroom.
So, why buy a 3500 lumen classroom projector? Depends what you are doing. Showing videos is always a good excuse for wanting a lot more lumens, as normal "presentations" tend to be high contrast, and work well, even with a healthy amount of ambient light, but video can often be medium bright, or even dark. That's when you want more lumens.
If you are looking for projectors for, say a larger, multi-purpose room, then definitely consider the brighter projectors. Remember, you need a projector with four times the lumens, to go from one sized screen to another, with twice the diagonal size while appearing just as bright.