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 f259 maximum lens aperture f287 minimum focal length 1688mm maximum focal length 2188mm minimum diagonal image size 762mm maximum diagonal image size 762m minimum projection distance 1m maximum projection