The Optoma DS311 has a maximum resolution of SVGA (800x600). That's 39% less resolution than the most frequently found native projector resolution of XGA (1024x768).
This data projector's resolution (SVGA (800x600)) is in fact the worst resolution across all 13000:1 contrast ratio multimedia projectors that were launched around the same time as the DS311.
A WXGA (1280x800) native projector resolution is the best resolution amongst comparable types of data projector.
It may also be worth considering one of the other data projectors that have a resolution of SVGA (800x600) currently available including the Benq MS504 ($308.99) which has a better Rating.
If the resolution of this 13000:1 contrast ratio data projector is not high enough for you then you might want to look at the Benq MX819ST ($613.99) (XGA (1024x768)) which also has a higher rating.