The KJ17ex7.7B is a portable HDTV production lens within the 2/3-inch image format sector of the new HDgc family. This particular lens is intended for users whose foremost priority is an affordable HD lens that delivers a generous range of focal lengths combined with a wide field of view in a lightweight mobile package. It was specifically designed for the many new cost-effective but remarkably high-performance 2/3-inch acquisition systems that appeared in 2008-2009.
In the KJ17ex7.7B lens imaging performance has been significantly advanced by mobilizing the most contemporary of optical glasses, optical coating materials and processes, and powerful new optical design tools. Customer feedback also spurred a total redesign of the digital drive unit that further optimized both the ergonomic aspects and the performance of the digital electronic control of zoom, iris, and focus.
The short 7.7 mm focal length translates to a 63.9 degree horizontal angle of view for the 16:9 HD image format. Combined with a focal range that has been extended to now cover a range from 7.7mm to 131mm (and 262mm with extender) this lens offers unsurpassed operational capabilities in a compact package weighing less than 3.5lbs. Focus breathing has also been significantly reduced over the predecessor lens.
ABOUT THIS LENS
The KJ17ex7.7B represents a new degree of optimization in meeting the demands for mobility in a handheld HDTV camera system and achieving the imaging quality sought in HDTV broadcast news acquisition while also essentially maintaining the price level of the original HDgc. The maximum relative aperture is F1.9 which, combined with the typically F-10/11 sensitivity specifications of the contemporary HD ENG cameras, ensures excellent video pictures in very low light environments. The image performance strategies of this new lens sought a tighter control of MTF across the entire image plane and with operational variations of zoom, iris, and focus. Minimization of monochromatic and chromatic aberrations and further maximization of image contrast combine with the improved MTF to produce superb picture sharpness.
Relative light distribution over the mid to long focal lengths is better controlled and this better uniformity of brightness across the image plane combines with the higher contrast and higher MTF to produce sharp clear HD pictures. Contrast was enhanced by excellent control of black reproduction using new multilayer anti-reflective optical coatings and new optomechanical design innovations that significantly reduced flare, veiling glare, and any internal reflections.
The lens spectral transmittance characteristic was closely coordinated with that of all of the major portable HD cameras to ensure adherence to the international HDTV colorimetric standard.
Four significant technologies converged to produce the KJ17ex7.7B portable HD ENG lens system that has been designed to partner with the most contemporary of the new tapeless 2/3-inch HD production cameras:
Newly developed optical glass materials each having unique dispersion characteristics allowed improved control over chromatic aberrations and geometric distortion. Lens element surface accuracy has been improved two-fold over those in the earlier HDgc lenses contributing to the improved MTF performance
- New Multilayer Optical Coatings combined with new deposition processes produce an improved optical contrast ratio
- Three-part Internal Focus is a Canon design innovation that reduces changes in aberrations when focusing to different object distances while also exercising improved control over any tendency for focus breathing
- New and more powerful computer design tools facilitated a greater degree of optimization of multiple optical variables in the lens design
- New fourth-generation digital servo systems further empowers the camera operator in terms of operational creativity:
- Enhanced Digital Drive technology based upon a totally new software platform provides precision microcomputer control of the three servo systems for zoom, iris and focus while also facilitating new developments in lens-camera correction of lateral chromatic aberration
- Unique Information Display and extended memory within the digital drive unit extends user-defined digital functionality
- Canon’s patented Micro Roofmirror Array (MRA) technology underlies the unique miniature 16-bit rotary encoders that are used for each of the zoom, iris, and focus position detection (each with a positional accuracy of 0.1 micrometer)
- Dynamic Zoom Speed Range can be adjusted from 0.5 seconds to 5 minutes (from wide to telephoto extremes)
- Extensive use of 3D CAD-CAM design facilitated a design that paid high attention to operator comfort and attendant lowering of fatigue during protracted shooting:
- Digital Drive Unit was totally redesigned to take into account the curved human hand that encompasses the unit with a view of shaping the unit for greater comfort and to better facilitate the actuation of lens controls. The unit shape also provides a wider separation that allows the other hand to more easily adjust the focus control. Finally, the drive unit was narrowed and its mounting angle on the lens set to allow the operator’s elbow to settle close to the body thus providing an important reduction in fatigue when operating a shoulder mounted lens-camera system
- Special Magnesium alloy body for light weight and exceptional durability
- Computer simulation of the optomechanical design allowed examination of optimized anti-reflection internal barrel coatings, and structural techniques (light blocking grooves and knife edges) that produced greater control over harmful light reflections within the lens barrel that can be stimulated by strong light sources
- All contemporary Canon lenses avoid the use of materials and substances potentially harmful to the environment. Lead has been removed from all optics and other identified substances from all components comprising the composite lens system.
|Object Image Format
|Object Image size
||9.59 mm (H) x 5.39 mm (V)
|Focal Length Range
|Focal Length Range with Extender
|Angular Field of View
||At 7.7mm 63.9° (H) x 38.6° (V)
At 131mm 4.2° (H) x 2.36° (V)
|Angular Field of View with Extender
||At 15.4mm 34.6° (H) x 19.9° (V)
At 262mm 2.1° (H) x 1.18° (V)
|Maximum Relative Aperture (F-Number)
||At 7.7mm~102.5mm 1 : 1.8
At 131mm (Ramping Characteristic) 1 : 2.3
|Maximum Relative Aperture (F-Number) with Extender
||At 15.4mm~205mm 1 : 3.6
At 262mm (Ramping Characteristic) 1 : 4.6
|MOD From Front of Lens
||0.6m (10mm with Macro)
|Scene Object Dimensions at MOD
||At 7.7mm 68.5 cm x 38.5 cm
At 131mm 4.2 cm x 2.4 cm
|Scene Object Dimensions at MOD with Extender
||At 15.4mm 34.3 cm x 19.3 cm
At 262mm 2.1 cm x 1.2 cm
||159.3mm 106.6mm 197.8mm 1.48kg (3.263lbs)
|Size Length mm mod1