| Optical Performance | Superb control of flare, distortion, veiling glare, and spherical aberrations at full aperture. |
| Focus Mechanism | The S4 design foregoes the usual helical thread method of focus adjustment in favour of Cooke's Academy Awardｮ-winning cam mechanism. The smooth cam movement liberates the lens from a simple thread rotation giving the operator an appropriate rate of focus at all distances. The cam design also allows for better spaced and more detailed and visible index marks. |
| No Breathing | No image shift when racking focus from close focus to infinity. |
| Color Balance | All focal lengths are color balanced, achieving excellent contrast and resolution over the full Super 35 format. |
| True T2.0 Aperture | Cooke Series 4 lenses are optimized at maximum aperture, measured at a true T2.0. |
| Operation | Focus and iris drive gears have the same diameter and position across all focal lengths reducing adjustment time when changing lenses: 140 teeth 0.8 Metric Module x 6.0mm Wide (98mm from image plane) |
| Iris Scales | Two opposing linear T-Scales, whole and third stops marked |
| Iris Angular Rotation | Total Rotation 91 degrees |
| Iris Drive Gear | 114 Teeth 0.8 Metric Module x 6.0mm Wide, (84mm from image plane) |
| Mount and scales | Each of the Series 4 Primes are supplied with PL mount and are available with either footage or metric focus scales. |
| Finish | Hard-wearing, scratch-resistant, PTFE anodised finish for working in the harshest environments. |
| Internal Front Fitting Filter | Internal Thread for Filter Adapter M105 x 0.75 pitch |
