Six Portable Projector Comparison - Image Quality
Overview
Image Quality
General Performance
Warranty
Summary, Pros, Cons
Digital Projector Image Quality
Sharpness
Overall all six projectors perform as advertised with an easy to read image, including small type. Of these the Optoma TX-700 produces a slightly softer image than the others, but still is easily readable on type as small as 8 points - smaller than you are likely to use in meetings or formal presentations (typical Powerpoint presentations use mostly 18 to 48 point type.
The two LCD projectors, "appear" a little sharper overall, but that is normal, and caused by the more visible pixel structure, as much as anything else, but it does provide that "razor sharp" feel. Again, though, all produce a more than good image sharpness.
The Epson Powerlite S4, remember is a lower SVGA resolution projector, the other five are all XGA (including the one WXGA ( widescreen XGA), the HD4000.
Many buyers of the S4 are schools standardized on SVGA resolution computers. Most of the rest of the world uses XGA as the current standard. When the Epson S4 is fed an XGA source, it uses compression technology to squeeze it to fit, so you see the full "page". This degrades the image quality slightly. Very small type starts getting a bit ugly and a little hard to read (8 to 10 point), from an XGA source.
Of course with a typical laptop, you can set it to output SXGA even if it's XGA or higher resolution. If you are using presentation software, like Powerpoint, everything scales, and things look very sharp. If, however you are feeding traditional meeting materiels, like spreadsheets for example, to output SVGA you would be displaying significantly less rows and columns, and that is easily detrimental. Instead you can always output the XGA, and suffer the slight compression technology losses.
I should note, that the SVGA projector market has remained strong for years, but is now starting to diminish. The advent of under $1000 XGA projectors has lowered the price spread between SVGA and XGA to as little as $200, but more typically $300. Most XGA users should be spending the extra for XGA native projectors, for a host of reasons.
Color Handling
This "separates the men from the boys" or to be politically correct - the kids from the adults.
Historically LCD projectors have had a major advantage in color handling over single chip DLP projectors. LCD models traditionally produce bright rich colors - all colors, including red and yellow. By comparison, DLP projectors have been known for struggling with bright reds and yellows. I was pleasantly surprised, however, by how good, overall this new crop of four DLP projectors did. While none of them rose up to match the two LCD projectors - the Panaonic LB60NTU and the Epson S4, three of the four came very close.
As a result five of the six models should, in terms of colors go, should be fine for all but the most incredibly critical color demands. The weakest of the six, the Optoma TX-700, still performed significantly better than the vast majority of DLP models just a year or two old. That said, if you need that really bright red or yellow, it does come up short.
Please see the Pie Chart and color bar examples in the individual reviews, but to "give you a taste" here are the best - the Panasonic LB60NTU, and the worst - the TX-700 on those Yellows and Reds:
Panasonic PT-LB60NTU and PT-LB60U:
Optoma TX-700:

As you can see, there is a real difference, most notably on the yellow slice, but it should not be a deal breaker on the TX-700 for many.
Projector Brightness
There were some big surprises here, as we tested each of these projectors for brightness.
I have listed the projectors here, in order of brightness - from the brightest to least bright. After the projector name there are two numbers. Claimed is the manufacturer's claimed brightness on their spec sheets.
InFocus IN26: Tested: 1221 lumens, Claimed 1700 lumens
Mitsubishi HD4000: Tested: 1341 lumens, Claimed: 2000 lumens
Optoma TX700: Tested: 1883 lumens, Claimed: 2200 lumens
Epson Powerlite S4: Tested: 2221 lumens, Claimed: 1800 lumens
Panasonic PT-LB60NTU: Tested: 2231 lumens, Claimed: 3200 lumens
Dell 2400MP: Tested: 2357 lumens, Claimed: 3000 lumens
Compression Technology
All of these projectors did a perfectly acceptable job of compressing the next higher resolution. Degradation is slight, and even the smallest type is readable, if not pretty. Compression on large type (presentation sized), is virtually unnoticeable, and a non isse.
One area where compression is an issue is if you are displaying graphics with very fine lines such as architectural and engineering drawings. If this is your "killer" app, you will want to purchase a projector who's native resolution is as high as what you want to show.
As noted above, the Epson S4, is the only one that needs compression technology to handle the tradtional XGA resolutioni computers. For those of you, with XGA computers, the S4 will do a respectable job, but the image quality will come up short compared to any of the XGA models.
The Mitsubishi HD4000 is the only widescreen projector in our review. This makes it a better choice, if budget allows, for working with widescreen laptops, as well as applications that are more suited to that wider aspect ratio, such as messaging and announcements, displaying the maximum number of columns in spreadsheets, etc. As widescreen business projectors (at least under $5000) is a new catagory, there are only a few units on the market yet. As more hit the market, prices should fall, over the next year or so, to come much closer to the pricing of typical 4:3 aspect ratio XGA projectors.
Video Performance
A real mixed bag here. The widescreen HD4000 is pretty much my first pick overall. The Optoma TX-700 and the InFocus IN26 both have that blend of smooth image and high contrast that DLP projectors are known for. The Dell 2400MP, the brightest of the field, does very good on almost every area of video, but one. It's weekness is a lot of noise in bright areas. Too much to really make it acceptable for serious use in the home. All of the DLP's can certainly double as part time solutions for watching sports and movies at home, and none rival dedicated home theater projectors. The Dell's noise level issue, however makes it the one lease able to double in the home from this standpoint - a shame considering it's low price and tons of lumens that would otherwise make it a great 4:3 solution for those who can't fully darken their rooms. And that is a very large market.
Based on price,and sheer number of lumens, the TX-700 is probably the best value for 4:3 portable projector as a bright home entertainment solution.
For typical business video or classroom video, however all six do a commendable job.
The Epson S4 and the Panasonic LB60 projectors each have the advantage of being LCD and not having a color wheel. As a result, they do not exhibit the "rainbow effect" that is visible by a small, but signicant number of users, with the 2X speed color filter wheels. Home theater models use 4X or 5X wheels, dramatically reducing the number of people who can detect the rainbow effect.
Perhaps this will help clarify: can only rarely detect the rainbow effect with home theater projectors, but had far less trouble noticing it with these DLP models. Note, it is "most visible" when motion (such as slow or fast panning) is combined with very bright objects on much darker backgrounds. For that reason, you are much more likely to see rainbows on a dark movie scene with some bright lights, than on a typical business video or educational movie where most scenes are going to be bright or medium bright not dark.
The tradeoff for the LCD projectors is significantly lower contrast levels. Details in dark areas are going to get lost. Again, the LCD models are fine for typical business and education, but the lower contrast levels definitely diminishes their performance as a home theater solution.
Now, its time to visit the General Performance comparison, where we consider non-image quality issues, like menus, remotes, lamp life....
Overview
Image Quality
General Performance
Warranty
Summary, Pros, Cons