Zoom Lens Light Loss. The 1.2x zoom isn't large enough to curtail brightness significantly at the telephoto end of the lens. You can safely ignore the potential light loss when choosing how far to put the projector from the screen. Throw Distance. Unlike most short throw projectors, the TH671ST offers a zoom lens, which adds flexibility for positioning the projector to help make setup easy. Simply place the projector at approximately the right distance from the screen, and then fit the image to the screen by adjusting the 1.2x zoom, rather than moving the projector. The range for a 110-inch 16:9 image is roughly 5.5 to 6.7 feet. The BenQ TH671ST Projection Calculator will let you find the throw distance range for the image size you want. Light Mode contains the four lamp levels. Normal is brightest followed by Eco which cuts output by about 35%. SmartEco throttles brightness and roughly doubles static contrast with occasionally visible image pumping. LampSave also varies output and extends lamp life to a claimed 15,000 hours.

LumiExpert is something I had not seen before. It works with an ambient light sensor on the chassis’ top and adjusts gamma on the fly according to your room’s lighting. In my test, it had a very subtle effect but I found better quality in my totally dark space with it left off. You can adjust the amount of compensation with a six-position slider. Video Optimized Lumens. Both the Cinema and Sport modes are good starting points for optimizing settings for video. Both deliver color that's well within a realistic looking range and close enough to accurate so you wouldn't know that any color is off without a reference image to compare to. However, Sport mode delivers a higher ANSI lumen measurement and brighter shades of yellow, which prove to be more accurate when comparing with a reference image.Impressive as the BenQ TH671ST is in 2D, it's only when you take advantage of the optional 3D system that the picture becomes truly immersive. Just add the optional BenQ 3D glasses, connect up to a suitable source and enjoy 3D images that are every bit as bold as at the cinema. Brightness Uniformity. The test unit's brightness uniformity is 63%. Somewhat surprisingly—because short throw projectors tend to have problems maintaining uniform brightness—this is actually a better than typical result for standard throw home theater projectors in this price range. Countering the trapezoid effect when the projector must be placed off-center, such as simple placement on top of a table, vertical keystone adjusts the image for a professionally squared image. Keystone correction makes it simple to project ideally aligned images from a variety of locations. TH671ST maximises thrills in minimal space, requiring as little as 1.5m to project stunning 100” pictures. The shortened throw enables carefree enjoyment without space constraints or setup hassles.

Those seeking to to improve contrast will want to experiment with the LumiExpert feature. LumiExpert detects the ambient light level and adjusts gamma appropriately for the lighting. You can also turn it off and adjust its setting to make the overall picture a little darker or a little brighter at any given ambient light level. We found that choosing the right setting can significantly increase contrast and the sense of three dimensionality in dark scenes. Given its design parameters, there is really nothing to complain about here. The BenQ TH671ST delivers accurate Rec.709 color, superb clarity, bright imagery, and low input lag just as promised. Though 3D isn’t a big draw for consumers any longer, it still looks great on this projector. With a compact chassis and short-throw lens, it can be set up just about anywhere. It’s small enough to be portable but that also makes it ideal for smaller media rooms where one might not have 10 or 15 feet of depth to throw a 100” image. The TH671ST can do it from just five feet away, on a coffee table, or hung from the ceiling. away from the screen or wall, the image will get bigger, and as you push the projector closer to the screen or wall the image will be smaller. To properly Brilliant Color is a feature I’ve seen on pretty much every BenQ projector and it works differently with each model. The TH671ST’s implementation is subtle. You can barely tell a difference between the on and off setting. Ultimately, I preferred the picture with it left off.

A short-throw projector full of features, all wrapped up in a sleek package.

calculator, you will see dimension lines that will tell you the height, width, and diagonal measurements of your image. Calculating a Throw Distance when you know the IMAGE SIZE

To determine the Image Size (screen size) enter a distance measurement number in the Throw Distance value box and hit the Enter Zoom Lens ring on your projector. The Zoom Range slider in the calculator will help you calculate the changes made by a Zoom Lens. With an outstanding brightness figure of 3000 ANSI Lumens, the TH671ST suits all types of lighting conditions. Even during daylight conditions with curtains or blinds open, the TH670 produces a watchable and detailed picture - perfect for gaming on a weekend afternoon. For optimal performance, BenQ’s LumiExpert technology detects lighting conditions and automatically adjusts the brightness to suit. Lens offset. The lens offset for the TH671ST is designed for placement on a low table, with the bottom edge of the image falling somewhere between the lens centerline and up to 5% of the image height above it. For example, with a 100-inch high image the bottom edge would be anywhere between even with the lens centerline and 5 inches above it. The bottom edge of the image on our test unit was about 4% of the image height above the centerline, which is within typical sample-to-sample variation.As with virtually all inexpensive home theater projectors we've tested, the brightness variation is easy to see with a 100% white or light colored image. With the projector sitting on a table, brightness is highest at the bottom center of the image, and gradually falls going up and to either side, making the upper left and right corners the dimmest. Those who are particularly sensitive to brightness variations may find this unacceptable. However the difference is hard to see with any image that breaks up the field of view.

Input lag. With Fast Mode on, the TH671ST's input lag is 16.4 ms in Bright and Sport modes and 16.6 ms in Vivid TV and Game modes. Both are fast enough for serious gamers. Input lag for Cinema mode is only slightly longer, at 18.8 ms. With Fast Mode off, the lag jumps to about 50 ms for all modes but Cinema, which is 52.2 ms. The default setting for Fast Mode is On for Game mode, and Off for all other modes. distance between the lens of the projector and the surface of the screen. On the graphical representation of a screen in the middle of theAmong the TH671ST's most noteworthy features is its 1.2x zoom, an unusual extra for a short throw. Any short throw lens lets you set up the projector close to the screen for a big image in a small room—for example, small apartments or dorm rooms. But a zoom lens adds convenience and offers greater flexibility of placement, letting you adjust the zoom, rather than move the projector, to match the image to the screen size. This is particularly welcome for portable use, where moving from one location to another means having to set up the projector each time. Portability is also enhanced by surprisingly robust audio for such a small projector. Note that we saw an occasional skipped frame when watching movies at 24 frames per second (fps)—though not at 60 fps. Skipped frames are usually visible as a random, judder-like jump (only bigger) in the middle of a camera pan, or in the movement of an on-screen object when the camera is fixed. It seemed to happen more frequently with LumiExpert on, however, these skips were rare and not reliably repeatable. BenQ has been looking into the issue to determine if it's isolated to our set-up or something that might require a firmware correction.