PERFORMANCE YOU NEED QUALITY YOU ... VTL-1634 VTL-2810 VTL-3580 VTL-550 ... Image Format Focal Length Max. Aperture Iris Operation ... 1/3" 1.6 - 3.4mm F1.4 Manual F1.4 - ... 1/3" 5.5 - 82.5mm F1.8 Manual F1.8 - ... 1/3" 2.8 - 10.0mm F1.4 Manual F1.4 - ...