Classroom Projector Report: Best School Projectors for Education - Image Quality
The 2012 Classroom Projector Report is sponsored by:
COMING SOON! The 2012 update of this page is in the works. In the mean time, the analysis from last year's report is still applicable. Check back on June 4th for updates.
5/19/2012 - Art Feierman
This section considers the general picture quality of the fifteen education projectors reviewed for the report. Let's start with color handling itself.
Classroom Projectors - Color Handling
Before going into talking color, a brief discussion of Color lumens vs White Lumens. For years, the ANSI standard has been to measure white. In recent years, some non-DLP manufacturers of projectors have been pushing for a formal Color lumens standard as well, or Color brightness standard. I'll discuss further elsewhere. The bottom line though, is that if a typical DLP and LCD both can put 2500 lumens of pure white on the screen, then the argument is that the LCD projector will produce more lumens if you measure pure colors; like red, green, blue, yellow.... There is validity to the argument, but in the performance section I'll try to provide some balanced insight.
It really comes down to this: As a general rule of thumb, when working with all but the very brightest preset modes of these projectors, the LCD projectors will almost all have very good color. Typcically the very brightest mode on a projector is usually labeled Dynamic (in one case Presentation). Whether LCD or DLP projector (or LCoS projector), most manufacturers will use that mode to push out the maximum in brightness and still have any vague color accuracy. In other words for most Dynamic modes good color is a luxury, max lumens is the goal.
On most projectors, however, the next brightest mode might be called Presentation, or Standard, or Normal, or... No matter, that second brightest mode (unless it's perhaps called Game) probably has very good color if it's an LCD projector, or could have anything from pretty good to so-so color performance for DLP projectors.
For the second year, we are pleased to report that just about all of the DLP projectors reviewed are doing at least decent bright reds and yellows in multiple modes, far better than just a couple of years ago, and better than last year's crop of reviewed projectors, when a couple of the DLP projectors had dark red wine colored bright reds, and ugly bright yellows that look mustardy, and with some green caste. If it's history class and the bright red of a flag comes out dark red... For most of these DLP projectors in their brightest modes, there is still a real tendency for those mustard yellows, and wine color when expecting bright red.
Move down into the dimmer modes (names like Cinema, Movie, Video, etc.) and the color improves, especially with the DLP projectors.. The main difference though is that with most LCD projectors, those modes are still pretty bright. On DLP projectors it's not uncommon for those best modes to surrender up to half of maximum brightness, to achieve their very best color. But, that best color is really good, as it is with the LCD projectors. This year no LCoS projectors in the report, to consider. Keep in mind, that while I refer to 3LCD as having an advantage, DLP for years dominated image quality among home theater projectors. It's just a matter of priorities.
So, while most, not all, DLP projectors are capable of very good color even in their dimmest modes, remember that: If you definitely need really good color, you can expect an LCD projector to deliver the same quality or better color, with more lumens than the DLP can provide.
Let's use some photos for comparison:
These examples are from last year's report. Below - our test color wheel image taken using the Epson Powerlite 85+ projector (3LCD) in Presentation mode. Despite being an extremely bright mode, color is excellent. Presentation mode on this Epson achieves about 90% of the brightness of its brightest - Dynamic mode.
Now consider this image taken with the Dell S300W DLP projector in Presentation mode. Not bad for a DLP, but note the yellows definitely pale compared to the Epson above, and with a touch of green in the "pure yellow" slice. The Dell, btw, though not the best of the DLPs reviewed here, is pretty good. Now look at the second image below - the Dell, again, but in Movie mode. Despite the exposure being a little darker in the second image, the yellow and pure red are better, and with more punch. Even the blues look better.
Finally, in the image below, that's the Epson again, in its Movie mode.That the yellow is still better, and the pure red the brighter, and the pure blue, more correctly. Also the blue purple next to the pure blue, looks about right on the Epson, but is still well too blue on the Dell S300W.
In a typical K12 classroom environment, few situations require the most accurate color, but, anytime the projector is used for video or photography, or anything with a lot of photos in it, the LCD projectors should have the advantage.
In our image below, this is the 3LCD Sony VPL-EX175 projector, in Dynamic mode (with the Sony, Dynamic has better color than Presentation).. Below it, the DLP Sharp PG-D45X3D, probably the DLP projector of this 2011-2012 report, with the best overall color.
My point is would be that if color is imporntant and you need the lumens as well, LCD is probably the logical way to go, all else being equal (it never is). If, when you need really good color on occasion, if you don't mind sacrificing more brightness when you demand it), then most of the DLP's can do a perfectly respectable job, and many of these projectors are, for perhaps 98% of users, provide color more than sufficient for the task at hand.
Below, some "real world content" samples (and not color charts): In order: Epson Powerlite 96W, Acer X1261P, Casio XJ-A250V, and Sharp PG-D45X3D (exposures vary).
Note, yes that's me standing to the right of the screen. -art
School Projectors: Sharpness
Discussion: Mostly we tend to quibble over sharpness in the different projectors' native modes, but all should appear nice and sharp, when handling source material that matches their true resolution. All of the projectors considered can "compress" higher resolution signals, and this will affect apparent sharpness when compressing the data to fit. Some manufacturers simply have better algorithms for compressing higher resolutions.
Having superior compression abilities is still important to many, but is less critical today, than in the past. Today, more and more, computers and projectors are designed so that you can have one resolution running on your computer screen, and a different one feeding the projector its native resolution should they not be the same to begin with. That really applies more to laptops, as desktops don't have their own "native resolution", but are dependent on graphics card and monitor. Still today's graphics cards are often also capable of outputing two resolutions - one to a monitor, one to a projector.
This year most of the projectors could handle UXGA - 1600x1200 resolution without difficulty. That's two steps up, from XGA, all the XGA and the WXGA 1280x800 widescreens were up to the task, though some looked better than others, all locked on to at least one of the UXGA modes on my MacBook Pro, or on Mike or Tony's PCs. Also of note, for the widescreen models, many support up to 1080i or 1080p.
Which is inherently sharper? LCD or DLP? The proper answer is almost certainly neither. Each has characteristics though, which may explain why some perceive one type of projector sharper than the other. Then, perhaps more importantly, it's not the type of technology, but the effort and importance sharpness plays when each projector is designed. Some projectors use plastic lenses, some use glass. Most are very good at everything, in that whatever softness seen, isn't likely to harm readability, except, on, perhaps, very small type, type sizes small enough, that many people would be sitting too far away to read it, no matter how sharp.
Above, the Casio XJ-A250V (Casio's newest "Green Slim" projector) is shown handling the highest it can tackle 1920x1080 (HDTV resolution) from a MacBook. You can click to enlarge. Type is definitely softer than lower resolutions, but remember at this resolution, everything is only 2/3 the size of the same data done at 1280x720. In other words, 12 point type appears smaller, the higher the resolution you use.
Above, the same Casio projector image, at native resolution.
Tech Tip: DLP's have smaller masks around each pixel, making that mask (the patttern) less visible. LCD's have more visible masks (though the amount of difference between the technologies has been shrinking). It is the slight visibility of the LCD mask, that actually causes many people to perceive LCD projectors as the sharper.
In reality, the real differences will tie first, to resolution. An image on an SVGA projector (800x600) will look softer than on an XGA projector, regardless of which technology is used with each projector. The higher the native resolution, the sharper things should be, overall, but: A projector will be sharpest in its native resolution. Therefore, a slightly higher resolution projector may not appear quite as sharp doing a lower res, as a step lower resolution projector will look projecting native resolution.
That's due to the fact that when you compress text (from a higher resolution) it does get softer. On photos and non-critical imagery, you are far less likely to notice any softness.
If you are going to be doing a lot of work with small type, such as spreadsheets, word documents, etc. it is definitely best to avoid needing compression to work with higher resolution source material. For that same reason, in the sciences, architecture, medicine, and some other specialty areas, there is demand for higher than XGA or WXGA resolution projectors. This is, however a rarity in the K-12 world even though the need for higher resolution projectors at the university level is rather significant.
Bottom line: For normal classroom consideration, sharpness should be a very minor concern. I have mentioned though, the ultra-short throw projectors. Some are better at having the data sharpness consistent across the whole screen. This is a focus issue, made more challenging by the close-in positioning, which makes it harder to have good sharpness from the center to the corners.
Of the two ultra-short throw projectors, the Epson definitely has the sharper image. That said, the Hitachi is sharp enough that the difference will not be a major consideration, especially considering the Epson's an interactive projector and this Hitachi is not. (Hitachi just announced two interactive projectors as this is going to publish.) Sharpness on ultra short throw projectors is something to investigate, or lets say, be aware of. I wouldn't go buying a number of ultra-short throw projectors without checking out the differences.
Projector Contrast and Blacks
I am so used to writing volumes about black level performance when reviewing home theater projectors. In the world of projectors for education, however, great blacks is rarely a concern (for photography), though good blacks are always appreciated.
Generally, DLP's produced the better natural black levels and had higher measured contrast for many years. These days, though, some business and school projectors are using dynamic irises to improve the numbers and the image.
For the most part, the contrast spec is supposed to give you an idea if the blacks are pretty black or just very dark gray, or somewhere in the middle. Projectors with contrast ratios of 300:1 or 500:1 or even 600:1 are on the low end of contrast performance side. Those numbers were typical of a lot of LCD projectors. This year, though, of the eight 3LCD projectors reviewed for this report, all rate 2000:1 contrast, except the Casio (1800:1), the Sanyo (800:1), and a big surprise, the Sony VPL-EX175, which claims the highest contrast in the report, of 4000:1. By comparison, DLP projectors typically start at 2000:1 for these projectors and some claim up to 3700:1 (Acer). All of the DLP projectors did claim at least 2000:1 this year. To get improved contrast though, most of the 3LCD projectors use a dynamic iris. That should be fine, but it's not as good as native contrast in terms of dynamic range.
The bottom line, is that of the projectors reviewed here, on mixed scenes (lots of bright and dark), the blacks will typically prove to be a little blacker with any of the DLP's than with any LCD projectors.
Overall, contrast and blacks won't be an issue except perhaps for teaching a course about photography or graphics. That's very different than home theater projectors, where incredible (dynamic) blacks (oh, say 100,000:1) are very good, but owners want even better. The thing is, in the education or business world one is not looking primarily at very dark scenes. That's when the better blacks make a difference.
If on the other hand, someone is teaching an Art or Graphics class or a better example, History of Cinema, where everyone's watching Citizen Kane, Casablanca, Star Wars and Blade Runner (if you don't know Blade Runner - it's time to! - and I realize that's not likely to be a K-12 class), then a projector with a 2000:1 or better contrast ratio may look dramatically better than some projectors still out there with 500:1 or 1000:1 on some of those very dark scenes. Keep in mind, a doubling of the contrast spec, makes only a small difference. Not one of these projectors, however, can match the dark level performance of all but the least expensive home theater projectors.
For typical classroom or business use, the contrast differences discussed here have to be considered minor, relative to getting the message across.