When I opened the box the Optoma ML550($474.00 at Amazon) came in, I was expecting to find a typical 500-lumen WXGA (,1280 x 800) projector, much like the Optoma ML500, which the ML550 is in the process of replacing at this writing. What I found instead was a new-generation design that copies the small size of first-generation 300-lumen LED projectors like the Optoma ML300 and boosts the brightness.

The ML550 is one more model in a group of similar 300- and 500-lumen projectors that are each built around a WXGA DLP chip and an LED light source. Until now, the 300-lumen versions have had the advantage for size and weight. The Editors' Choice 3M Mobile Projector MP410, for example, weighs just 1 pound 13 ounces including its power block and cable, while the typical 500-lumen model weighs between two and three pounds.

The ML550 is lighter than the 3M MP410, at 14 ounces by itself or 1 pound 3 ounces with its power block. It's also a touch smaller, at 1.5 by 4.1 by 4.2 inches (HWD). And, of course, it's brighter too. However, the ML550 doesn't match the MP410 for image quality, which is enough to keep the 3M MP410 as Editors' Choice.

Basics

Optoma ships the ML550 with a soft carrying case that's large enough for the projector and power block as well as the included cable and credit-card size remote. Also helping make the projector even more portable is that you can read files directly from the 1.5GB internal memory, from USB memory keys, or from microSD cards.

Setup is standard. The USB A port and microSD card slot are on the back, along with an HDMI port and proprietary port for the included adaptor cable, which can plug into a VGA port at the other end. The HDMI port supports MHL for easy connection to most smartphones, as well as to a video source or computer.

If you get Optoma's optional Wi-Fi dongle ($99 list), which plugs into the USB A port, you can also connect by Wi-Fi. Optoma says it has free wireless apps available for Windows, Mac, iOS, and Android devices.

Also on the back is a Kensington Lock slot, so you can leave the projector sitting in a conference room without worrying about it disappearing. And note too that, as with any projector with an LED light source, the LEDs are meant to last the life of the projector. Optoma rates them at 20,000 hours.

Brightness
A 500-lumen projector obviously isn't as bright as today's typical conference-room model with a 3,000 lumen or higher rating. However, it's brighter than you might think. Based on SMPTE (Society of Motion Picture and Television Engineers) recommendations, and assuming a 1.0 gain screen, 500 lumens is suitable for an 85- to 115-inch diagonal image in theater dark lighting at the ML550's native 16:10 aspect ratio. Even in moderate ambient light, it's bright enough for a 56 to 63-inch diagonal image.

The reality is a little more complicated, because, as with most DLP-based projectors, the ML550's color brightness isn't the same as its white brightness in at least some modes. (For a discussion of color brightness, see Color Brightness: What It Is, and Why You Should Care.) As a reality check, I found it bright enough in my tests for comfortably viewing a 92-inch diagonal image in theater dark lighting.

Image Quality
Data image quality is best described as more than acceptable for most purposes. Video is one step below that, making the projector usable for video, but far from impressive.

On our standard suite of DisplayMate tests, colors were generally well saturated and eye-catching, but a little off in some cases, and significantly different using different preset modes. Red, for example, was a little dark in some modes, in terms of a hue-saturation-brightness color model, and a distinctly off hue orange-red in Cinema mode.

The more important problem for data screens is scaling artifacts at the projector's claimed native resolution. The same issue shows in every competing 300- and 500-lumen projector we've tested, and is related to the DLP chip these projectors use. That makes it expected, but, as I've discussed in detail in other reviews, it simply shouldn't happen.

The most obvious of these artifacts (in the form of unwanted extra patterns) won't be a problem for most people, because they show up only on images with closely spaced patterns of dots or lines over a large area. However, the scaling can also affect fine detail. With white text on black, for example, the text was easily readable at 8 points, but not at smaller sizes. Black on white text was easily readable at 9 points, but not at 7 points.

Very much on the plus side, the ML550 shows fewer rainbow artifacts, with light areas breaking up into red-green-blue rainbows, than most DLP projectors. The only time I saw them in data screens was with one test image that's designed to make them show. With video, they showed infrequently enough with color scenes that it's unlikely anyone will be bothered by them. On the other hand, they showed often enough in a black and white test clip that anyone who sees them easily would almost certainly find them annoying.

Two other features that demand mention are the ML550's audio, with a built-in one-watt speaker, and its 3D support. As with most small projectors, the volume is too low to be useful in most circumstances. If you need sound at a reasonable volume, plan on using a separate sound system. The 3D support is also limited. Optoma says it will work only with VGA connections and only with resolutions up to XGA.

If the Optoma ML550 offered even a little better image quality, it could easily be Editors' Choice. As it is, the 3M Mobile Projector MP410 does just enough better on that score to make up for its lower brightness and slightly heavier weight. If you don't need to show fine detail, however, you may never notice the difference in quality with the Optoma projector. And even if you do, you may be willing to give up just a little quality in favor of higher brightness. In either case, the Optoma ML550 is worth considering. You may well decide that the higher brightness is worth any potential loss in image detail.

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