Auto Focus Technology

Auto Focus Technology

Recently there has been a greater demand for broadcast HDTV production and the requirement for accuracy in focusing has risen in response to this demand. Canon has been and continues to be a pioneer in the design of broadcast lens and meets this demand with the introduction of a revolutionary HDTV Auto Focus System. For many years the market has been requesting this unique technology for HDTV production and the Auto Focus System has now been adapted into several of Canon’s DIGISUPER HDTV zoom lenses, the DIGISUPER 100 xs, the DIGISUPER 86 xs and the DIGISUPER 27.
This technology assists professional camera operators in concentrating on the action/ beauty shots while maintaining the images in focus. Canon’s advanced Auto Focusing for the DIGISUPER HDTV Zoom Lens employs the TTL-Secondary Image Registration Phase-detection system, originally developed for single-lens reflex still cameras, in order to pursue both high accuracy and a high tracking capability for broadcast HDTV.

DIGISUPER 100AF

DIGISUPER 86AF

DIGISUPER 27AF

Main Features of Canon's Auto Focus Function

• Extremely high focusing accuracy in full HDTV specifications
• Ability to focus from a completely de-focused status without hunting
• Ability to focus on a high speed moving object
• Size and position of the AF frame (target area) in the camera
VF can be changed from the Focus Demand FDJ-P31/P41.
(The size of the AF Frame can be changed in 3 steps)
* Please confirm the AF camera-lens interface with your camera manufacturer of choice
• Two operation modes (Full Time AF / Part Time AF) of the Auto Focus system is the answer to a professional camera operator’s various demands.

AF Frame
The camera operator can focus on a specific object by controlling the position of the AF Frame (target area) in the viewfinder from the Digital Focus Demand FDJ-P31/P41. The size of the AF frame (target area) can be changed in 3 steps allowing for different subjects and compositions.

AF Operation Mode
The AF system’s two operation modes is the answer to a professional camera operator’s various demands.

2 kinds of AF Operation Modes with ACTIVE/HOLD switch
Mode	FULL TIME AF	PART TIME AF
How AF works	Usually activated Focus position is locked while the SW is pushed.	Usually off. Activated while the SW is pushed.
Recommended Application	Sporting event etc. To follow a moving object.	Studio production etc. To confirm the best focus position.

How the Auto Focus Works

Structure of DIGISUPER HDTV Zoom Lens with Auto Focusing

TTL-Secondary Image Registration Phase-detection System
The light transmitting through a pair of the secondary imaging lenses focuses on separate sensors. The following figure illustrates this state of focusing. The TTL-Secondary Image Registration Phase-detection System determines the positional relationship between the two images (Refer to “d” in figure) to detect the amount and direction of defocusing.