Our goal for projector testing is to create a test script that, first, lets us report meaningful information based on objective results (in the form of quantitative measurements and qualitative observations), and, second, to define a consistent test procedure to ensure that our results are fully comparable from one review to the next. The Test ProcedureWhen testing projectors, it's important to first let the equipment thoroughly warm up to ensure stable performance, so our first step in testing is to turn the projector on and make sure it will stay on continuously by disabling any settings that might turn it off or put it in an idle (aka, sleep) mode. During the 30-minute warm-up time, we run through preliminary setup steps. This includes connecting cables and positioning the projector at the right distance from the screen to get the image size we need for testing. We test all projectors that include a zoom control for image size (as opposed to a digital zoom, which enlarges only part of an image) at maximum zoom and then adjust the image to the right size by moving the projector closer to or further from the screen. For most projectors, we set the image size to 2 meters across (the height varies, depending on the projector's aspect ratio). For projectors than can't throw (read: project) a bright enough image to be usable at that size, we adjust the size as necessary, usually to a 1-meter-wide image. More Preliminaries and SetupWe also use the warm-up time to browse through the on-screen menu system to get familiar with the menus and the controls on both the projector itself and the remote control, assuming one is bundled. Another reason for browsing through the menus is to take note of any settings that might require testing beyond what we normally do (with a given setting both on and off, for example). We make sure that any features that might affect our results are set properly. In particular, we turn off digital keystoning, which can introduce artifacts on some images. (We also test automatic keystone control with the feature on as well, to make sure it does what it claims to do.) Finally, we set our image sources—computer, Blu-ray player, or both—to the appropriate resolutions for testing. We set the computer to match the native resolution of the projector, which avoids artifacts introduced from the projector scaling the image up or down, and we run our video tests with the Blu-ray player set to the highest-resolution input for video that the projector supports, which in most cases is 1080p. Once the projector is warmed up, we take advantage of a series of setup screens in the DisplayMate program we use for testing to confirm that the projector is properly focused; that it's set to show the entire image without losing any pixels on the outer edge; and, for analog connections, that it's synched as well as possible to the incoming signal. The TestsBecause there is no fundamental difference between data projectors, home entertainment projectors, and home theater projectors, and there is a great deal of overlap in capability between categories, we run all projectors through both our data projector and core video projector tests if at all possible. There are a couple of exceptions, however. We have no choice but to skip tests for a given projector if it lacks an appropriate connector or lacks support for a given input resolution. For example, some pico projectors offer neither a VGA connector nor a digital connector for a computer, which prevents running the data projector tests. Similarly, some projectors may lack support for 1080p resolution for video tests, in which case we test with the highest input resolution that will work with the projector. For both data and video tests, we use the simplest screen possible—a white screen (gray screens effectively increase contrast ratio) with a 1.0 gain (higher gains concentrate the reflected light into a narrow cone, making the image brighter within that cone than it would otherwise be), and without any ability to absorb ambient light. The point is to make sure our observations are based strictly on the projector's abilities, as opposed to the screen we're using. For our data projector tests, we use DisplayMate, which consists of a set of images designed to bring out any problems that a projector (or other display) may have. Each image is designed to test a specific aspect of a projector's imaging capability. The full set of tests constitutes a thorough vetting of any given projector's abilities as a data projector. Our video tests center around the three video resolutions that are currently most relevant to real world use: 480p, 1080i, and 1080p. The 480p resolution is typical for connection to a cable, FIOS, or similar set-top box when watching non-HD channels, even using an HDMI or component video connection. It's also the resolution for DVD playback with an older DVD player, although most current models will let you upscale the output to a higher resolution. The 1080i resolution is the typical resolution for connection to a set-top box when watching HD channels and using an HDMI or component video connection. Lastly, 1080p is the resolution for a Blu-ray player over an HDMI connection as well as the most commonly used upscaling setting for DVDs when using an HDMI connection. For all projectors, we view clips from both DVD and Blu-ray discs. The clips are chosen to highlight how well the projector handles motion, facial colors, and challenging lighting conditions. We report on each of these issues, as well as any other relevant observations. We run these tests at the highest resolution the projector can accept as input, letting the Blu-ray player upscale the DVD images, which is what most people typically do. What this translates to is that for any projector that can accept 1080p input, which includes the overwhelming majority of projectors today, we set the video source to 1080p. For projectors that can't accept 1080p, we use the highest resolution they can accept. For home theater and home entertainment projectors, we also connect the projector to a FiOS box to view input at 480p and 1080i. Recorded clips from sports, taped shows, and movies ensure that we're looking at the same selection of video for each projector. Stereoscopic 3D is available today on almost all DLP projectors and even most recent LCD home theater and home entertainment models. In many cases with DLP projectors, however, it works only with input from computers, which limits its usefulness. In other cases, it supports 3D over an HDMI 1.4a port, which means you can use it with 3D-capable Blu-ray discs as well. We run our 3D tests, using a Blu-ray player for all projectors that support 3D over an HDMI 1.4a port. The clips are chosen to highlight how well the projector handles the same issues we examine for 2D video, plus the 3D-specific issues of crosstalk and 3D-related motion artifacts.

weiterlesen: RSS Quelle öffnen