The Optoma ES556 has a maximum resolution of SVGA (800x600). That's 39% less resolution than a XGA (1024x768) data projector, which is the most frequently found resolution.
A SVGA (800x600) projector native resolution is actually the worst resolution amongst all projectors of a similar age and spec to this data projector.
A 1080p (1920x1080) projector native resolution is the best resolution across comparable types of data projector.
What does "projector native resolution" mean?