To say that the Optoma TW610STi ($1,000 street) is simply the Editors' Choice Optoma TW610ST ($1,000 street, 4 stars) with interactivity added is an oversimplification, but not by much. Both models are built around a DLP chip with WXGA (1,280 by 800) resolution, and both share most of the same specifications, including a 3,100 lumen rating. However the two performed slightly differently on our tests, and the interactive feature puts the TW610STi in a completely different category. That said, one other thing the two have in common is that both are easy picks for Editors' Choice.

Short-throw interactive projectors like the TW610STi and the Acer S5201M ($900 street, 3 stars) that I reviewed recently earn their own category primarily because of price. On the one hand, they're more expensive than otherwise equivalent projectors without interactivity. (The current price for the TW610ST , for example, is $900). On the other hand, they're a lot cheaper than equivalent ultra-short throw interactive projectors, like the Editors' Choice Optoma TW675UTi-3D ($1800 street, 4 stars), with its expensive, ultra-short throw lens.

Short Throw vs. Ultra Short Throw

If you can afford an ultra-short throw projector, it's generally the preferred choice, since it will give you a large image from even closer to the screen. Most need only 10 or 15 inches from the front of the projector to throw the 78-inch wide image we use for most testing. That means you won't have to worry about casting a shadow when you stand near the screen to interact with it.

Short-throw projectors sit farther away. I measured the distance for the TW610STi at 40 inches for a 78-inch wide image. That's a lot closer than the 9 or more feet a standard-throw projector needs, and close enough so you still don't have to worry too much about shadows. That, plus the obvious advantage of a lower price, helps make the short-throw option an attractive alternative to anyone on a tight budget.

One other advantage for short throw projectors is that they tend to be more portable than equivalent ultra-short throw models. The TW610STi in particular weighs just 6.9 pounds, making it light enough to carry with you if you need to give interactive presentations on the go, or even just carry by hand from room to room.

The Basics

In most ways, the TW610STi is a typical projector for its size and weight. Setup is standard fare. Connection options on the back include an HDMI 1.3 port for a computer or video source, two VGA inputs for computers or component video, and both S-Video and composite video ports. There's also a USB A port you can use for either a USB memory key to read JPG and other image file formats directly, or for an optional dongle ($30 street) to connect by WiFi.

As with most interactive projectors that use a DLP chip, the TW610STi takes advantage of Texas Instrument's approach to interactivity, which eliminates the need for calibration. Simply turn on interactive mode and point the supplied wand (or pen if you prefer to call it that) at the screen. The projector adds a grid (invisible to the human eye) over the image. The wand uses it use to report where you're pointing. In addition, the wand only has to see the screen rather than touch it, which means you can turn literally any surface into the equivalent of an interactive whiteboard.

Brightness and Image Quality

Optoma rates the TW610STi at 3,100 lumens. That's bright enough for the image size in my tests to easily stand up to the level of ambient light in most offices. More important, unlike most interactive projectors, it doesn't drop much in brightness when you turn interactive mode on.

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The TW610STi also did well on data image quality on our standard suite of DisplayMate tests. Yellow was verging on a mustard color, but colors were generally well saturated and vibrant; color balance was excellent, with suitably neutral grays in all shades from black to white; and both black on white and white on black text was highly readable at all font sizes we test with.

Video quality is best described as good for a data projector. I saw some posterization (shading changing suddenly where it should change gradually) and some moderate loss of detail based on shading in dark areas. However both issues were obvious only in test clips that we use because they tend to cause the problem. Most data projectors do far worse.

The one potentially serious issue for video is relatively obvious rainbow artifacts, with light areas breaking up into little red-green-blue rainbows when you shift your gaze or an object moves on screen. I see this rainbow effect relatively easily, and didn't see it often enough with data screens to consider it bothersome. However, as with most DLP-based data projectors, the TW610STi shows rainbows more often with video, and anyone who's sensitive to the effect will likely find it annoying.

One other image quality issue is the TW610STi's electronic equivalent to an auto-iris, which lets the projector automatically adjust to make dark images darker. As with similar features on any number of other projectors, there's a noticeable lag between the image showing on screen and the feature reacting, which can be annoying. The feature is on by default, but you can easily turn it off if you don't like it.

Other Issues

Also under minor issues were one or two apparent glitches in the firmware. Several times during my testing, for example, the projector woke up in grayscale mode when I turned it on, even though there is no such mode in the menu system. However, getting color back was a simple matter of switching to a different color mode and then back again, so I count this as more of a curiosity than an actual problem.

Very much in the plus column is the TW610STi's audio quality, which is better than average for a projector in this weight class. The two 5-watt stereo speakers put out enough volume to fill at least a small conference room.

Also worth mention is the 3D support using DLP-Link glasses. The TW610STi's 3D works both with computers with Quad Buffered, Open GL 3D-compatible graphics cards and with video converters that convert Blu-ray 3D output to 720p 3D. As with all projectors that use expensive 3D-glasses—currently $70 or more each in this case—there's a question about how practical this can be for large audiences. However, the feature is available if want to use it, and unlike most interactive projectors with 3D, the TW610STi will let you turn on both 3D mode and interactive mode at the same time.

The Optoma TW610STi offers a lot to like, with its short throw, bright image, excellent data image quality, and better video quality than most data projectors. Being 3D-ready also helps guard against obsolescence, especially since you can use the 3D and interactive modes together. All this adds up to a highly attractive balance of features for a short-throw interactive projector, and that translates to making the Optoma TW610STi Editors' Choice.

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