Portable LED Projector
December 16, 2013
Highly portable. The ML550 measures 1.5" x 4.1" x 4.2" (HWD), and it weighs just 0.9 pounds by itself. Packed in the soft carrying case it comes with, along with the power block, power cord, remote, and combination VGA and audio out adaptor, the weight tops out at a still highly portable 2.3 pounds. Also adding to its portability is that it can read photo, video, audio, and Microsoft Office files directly from a USB memory key, microSD card, or internal memory, so you don't have to carry anything else with you. And the HDMI port lets you show images from any phone or tablet that supports MHL.
Low running costs. Optoma rates the LEDs in the ML550 at 20,000 hours, which means you should never have to buy replacements.
Brightness. I measured the ML550 at 414 lumens in its brightest predefined image mode and at 260 to 312 lumens in other modes. That makes the projector bright enough for extended viewing with a 48" diagonal image with moderate ambient light, or for a somewhat larger image for short sessions or dimmer lighting. I also measured a difference between white brightness and color brightness in Bright mode but not Cinema mode, which explains why Cinema mode offers the best color quality.
Good brightness uniformity. The projector did a good job maintaining uniform brightness, at 80% uniformity. You can see the difference with a solid color screen, but not with text, graphics, or video on screen to break up the image.