Technical specification projection system dlp projection method ceiling front rear 3d compatibility dlp 3d video compatibility edtv hdtv ntsc pal sdtv secam computer compatibility mac windows projection lens lens type manual focus manual zoom minimum lens aperture f256 maximum lens aperture f28 minimum focal length 21mm maximum focal length 2310mm minimum diagonal image size 60960mm maximum diagonal image size 762m minimum projection distance 1m maximum projection