Parfocal lens design allows you to maintain precise focus while using the zoom control. Constant T3.0 throughout the 16mm to 28mm zoom range Reduced breathing so you can focus on the scene and not the lens Smooth, de-clicked, 9-bladed, curved iris. Virtually no image shift when using the zoom control during filming Aspherical elements and Super-Low Dispersion glass reduce distortion and increase optical performance. 4K image ready Durable, all-metal cine-style housing with geared manual zoom, focus and aperture rings for use in follow-focus systems. Common 114mm front diameter for use with a wide variety of matte boxes and accessories