Nikon F5: Focusing Controls and Systems
Now, Nikon has taken another giant leap forward with the development of the Nikon F5's completely new autofocus system. It combines speed with accuracy and expands the range of performance. Pictures can be accurately focused at motor speeds about 60 percent faster than any other system.
The F5's operation is elegant. Not only is focus fast, but the new technology also provides advancements in more creative composition applications. The photographer has easier, more effective control with a "mouse-like" keypad. Nikon has built the fastest and most accurate AF system ever developed, and it is a tool that most creative professionals will enjoy using.
Meeting the real-world needs of professional photographers in the field, the Nikon F5's system delivers the best performance through the new Multi-CAM 1300 Sensor, a newly designed CPU, a Wide-Cross Array with five detection areas, a wide selection of focusing modes and options, and the delivery of a system that handles high-speed Focus Tracking at up to eight frames-per-second (fps) film advance speed.
Details on these new advances and how they can be used in the field follow. While each aspect of the new AF system is impressive, keep in mind that the integration of these technologies, and the goals they have achieved, are perhaps the most impressive feats of all.
The autofocus (AF) technology designed into Nikon's F5 is geared toward one goal -- giving it the fastest, most versatile and reliable autofocusing system ever. When AF technology first appeared, professional photographers were often reluctant to use it on the job, partly because they mistrusted any technology that took shooting control out of their hands, and partly because AF technology could not meet all the required standards of performance.
The technology evolved through time, and while autofocus began to operate faster, it could not achieve the accuracy that many photographers demanded. Taking more pictures, with expectations that some sharp ones would be found in the collection, became the way many photographers operated. Nikon has always combined speed of operation with accuracy, because in Nikon's view, speed is nothing without accuracy.
Thanks to Nikon Research & Development, speed has evolved to a new level without sacrificing accuracy. In fact, accuracy has been improved with newly developed technology and software design.
The Nikon N90s camera's wide-area cross sensor, combined with Nikon's AF-I Nikkor optics, gave photographers their first glimpse of what was possible with autofocus. They no longer needed to rely on a large quantity of pictures to obtain a certain number in focus. Now, photographers can expect both speed and accuracy. The N90s was a major advancement for professional photography in fast- moving situations.
The F5 Autofocusing Systems
The autofocusing systems in the new Nikon F5 offer photographers the world's fastest and most responsive focusing ever. The newly designed Multi-Cam Autofocus sensor features a Wide Cross-Array with five sensing areas that handle both vertical and horizontal compositions and action.
The performance is astonishing -- accurate autofocus is possible at the camera's fastest framing rate of eight frames-per-second when used with the optional nickel metal hydride power source. Speeds to 7.4 fps are achieved with the standard eight AA alkaline battery pack.
Other factors that add to the performance of the autofocus system include the newly designed CPU that provides enhanced detection speed and accuracy; Nikon's exclusive Dynamic AF mode, which automatically shifts from one focusing area to another to maintain sharp focus on moving subjects; and Focus Tracking with Lock-On,™ a system that anticipates subject movement with a feature that continues to hold focus on subjects even when they may be momentarily blocked or stray from the focus-detection area. Even details such as Nikon's new Mirror Balancer add significantly to the autofocus performance. Multi-CAM 1300 Sensor Module and Wide-Cross Array
The Multi-CAM 1300 sensor module was designed for the F5. It incorporates five AF sensors to create a large, Wide-Area Cross-Type array that provides greater coverage than any other AF system. Action oriented photographers will not be disappointed.
The three horizontal sensors are full-time cross-type sensors, which form a line covering 44% of the horizontal width. Each of the three cross-type sensors incorporates a cross pair for normal focus detection, and a second cross pair for detection in low light. This dual system maximizes AF speed and accuracy under the widest range of light conditions. The top and bottom sensors of the cross-array are line sensors (not cross-type), and together with the center cross sensor of the horizontal line, form a line of sensors which extends vertically, covering 30 percent of the vertical dimension of the viewfinder. Unlike other systems, the cross-type sensors in the Multi-Cam 1300 work full-time with every Nikkor lens, not just with lenses of f/2.8 maximum aperture, but with every AF Nikkor lens -- even those with maximum aperture of f/5.6.
The Wide-Cross array is displayed on the top-panel LCD of the Nikon F5. Within the viewfinder, there is a focus confirmation signal in the LCD area, and an Electrochromic display which defines the five focus detection areas. Additionally, via the Custom Setting operation of the F5, a series of LED signals can be activated, with each signal used to provide an additional indication of the operation of the AF detection areas. The LED "pointers" are located outside the edge of the viewing area, providing an illuminated reference for AF operation. Selection of any one of the five detection areas is made via the Focus Area Selector Keypad on the back of the F5 camera body. The Focus Area Selector Keypad is also provided on the optional Data Back and Multi-Control Backs.
Fast and accurate autofocus operation is achieved through a comprehensive set of features, including a system of micro-electronics and mechanical components. To achieve AF operation at motor speeds up to 8 frames per second requires exceptional precision, critical timing and robust construction.
For the Nikon F5, as a subject's distance changes, the Central Processing Unit, through the focus detection sensors, receives and processes focus status data. High-torque coreless motors with low power consumption drive each lens' AF operation, the shutter and film transport. The F5's mirror plays an important role in AF operation. Using a patented balancer, the F5's reflex mirror is able to move with precision and speed, and with no meaningful mirror bounce. This combination of high performance components helps the F5 achieve its benchmark combination of speed and accuracy.
AF Modes and Options: Dynamic or Single Area AF, Plus Single-Servo and Continuous Servo AF
The Nikon F5's AF systems are unmatched in versatility; photographers can choose among a number of options, and even customize these options to match the subject and shooting conditions.
Dynamic AF mode allows the photographer to designate one of the five AF sensors as the primary sensor. Once chosen, the primary sensor is used as the sensor for the first detection of the subject. If the subject distance changes, the sensor will detect the change and AF operation will begin. If the subject moves out of the area of the primary sensor, then the Nikon F5 will detect this movement and automatically scan and change the sensor so that the subject's movement can be followed and sharp focus can be maintained. Through Nikon's powerful software for Focus Tracking with Lock-on, even the brief moments that a subject may be between sensors do not disrupt focus. This system is ideal for sports, action and nature photography, effectively eliminating the "bulls-eye" centered shots. Dynamic AF can handle quick action, changing speeds and changing angles of motion.
Single Area AF mode offers the photographer creative control by presenting a choice of five precisely positioned AF spot sensors. The photographer selects which sensor to use by pressing the keypad on the back of the camera. Subjects detected by the chosen sensor area will be in sharp focus, virtually instantaneously. This is perfect for off-center subjects and eliminates the need to lock focus and recompose. It encourages visual exploration because it eliminates any extra steps to attain sharp focus.
There are two AF Release modes: Single Servo AF and Continuous Servo AF. The former is focus priority; the shutter will not release until focus has been confirmed. The latter is release priority; the shutter will be released when the photographer presses the shutter button. Custom settings allow the photographer to interchange focus and release priority in each mode. In manual focus, or when AF is activated separately from the shutter release button, the Nikon F5's two secondary AF Start buttons -- one for horizontal and one for vertical shooting -- come in handy.
Focus Tracking with Lock-On
When subjects go into motion, photographers need an AF system that will keep pace. That's the idea behind Nikon's Focus Tracking. When the subject begins to move, Focus Tracking is automatically activated, regardless of the AF mode or AF area mode selected. With the five area Wide-Cross Array AF sensor module, this computer-assisted system analyzes the speed of the subject as it drives the autofocus lens in anticipation of subject movement. This makes focus detection possible regardless of the direction of motion, even at the rapid 8 fps.
Aiding this amazingly fast response is the continuous overlap servo method of processing AF data. Some AF systems collect focusing data and process it in "blocks," then focus the lens in a stepped or intermittent method. The F5 lens continues focusing even during data processing, which results in more consistently sharp focus. Performance tests demonstrate that the Nikon F5's AF system can Focus Track on subjects moving faster than other systems. With a 300mm AF-S Nikkor lens, Focus Tracking can handle a subject, such as a race car, moving at a rate of 200 mph at a distance as close as 66 ft.
Lock-On is an exclusive Nikon AF feature that overcomes momentary interruptions in focus caused by an obstruction in front of the lens (such as a swaying tree branch in the woods) or a secondary subject that may briefly interrupt the point of view (such as a defensive end dashing across the field). This also applies if the photographer accidentally moves the AF sensor area off the main subject for a moment. Lock-On is key to maintaining focus during fast action shooting. With other systems, the autofocus detector will either "snag" on the obstruction, or will cause the lens to rack forward, thus losing the prime target.
Focus Tracking in the Nikon F5 can be used in any AF mode, AF area mode or film advance mode. Other systems require the camera to be set to continuous servo mode for Focus Tracking to be activated. Focus Tracking with Lock-On is also available in the Nikon N90s.
Wide EV Range: AF even in Dim Lighting
The F5's Multi-CAM 1300 operates in the widest EV range available -- EV minus 1 to EV 19. EV-1 equals an exposure of f/2 at eight seconds with ISO 100, a lighting condition so dark that even the human eye may have trouble focusing. When necessary, using a Nikon AF Speedlight (SB-26, -27 or -23) allows for autofocus even in total darkness via an LED light pattern that is emitted onto the subject. Setting the camera's AF mode to single servo and selecting the center focus area will activate the AF illuminator. Secondary AF Start Buttons
As mentioned, photographers have a number of options in AF modes and AF Release modes -- they can choose focus or release priority in both single- and continuous- servo modes. In many cases, joining the shutter release and focusing operations is desirable. However, there are conditions when separating the two functions comes in handy; photographers can concentrate on shutter release timing. This is invaluable for peak sports action and wildlife photography when capturing the decisive moment requires the keen concentration and instincts of the photographer.
There are two secondary AF start buttons -- for horizontal and vertical shooting. AF activation can be transferred to the Secondary AF Start buttons by using Custom Setting #4. This also allows for a quick changeover between autofocus and manual focus operation.
Available with the optional MF-28 Multi-Control Back, Freeze Focus automatically fires the shutter when a subject enters a pre-selected plane of focus. This ensures tack-sharp images for wildlife photography, macro-photography and remote photography. When used with manual focus mode, photographers can capture images of animals as they move down a track. Photographers can also use freeze focus for sports, fashion, stock or botanical shots in the field. Freeze focus operates with either AF or manual focus.
Offering more versatility than optical rangefinders, the Nikon F5's Electronic Rangefinder is a manual focusing aid that also indicates the direction of lens rotation to lead to sharpness and confirms focus. This feature can be used with AF Nikkor or other manual focus AI-type Nikkor lenses with a maximum aperture of f/5.6 or faster. AF Nikkor Lens System
Nikon offers an extensive selection of AF Nikkor optics, including AF Nikkor, AF-I Nikkor and AF-S Nikkor. All lenses work with the Nikon F5's F Lens Mount, and interface with the extensive communication of the mount.
AF Nikkor lenses are focus-driven by the F5's built-in AF high-torque coreless motor. Connecting to each lens via a drive control, AF operation is fast and accurate. The F5's motor responds instantly to the commands of the AF computer. Every AF Nikkor lens will operate with the F5's system faster than ever -- because the Nikon F5 has a more powerful AF drive system. The investment in AF Nikkor lenses is a good one for professionals and amateurs alike.
AF-I Nikkor lenses feature a built-in AF drive motor. They autofocus with near silent operation, and are fast and accurate. The newest Nikkor lenses with built-in AF drive system include the AF-S Nikkor lenses. With their Silent Wave Motors, they are the fastest and most accurate performers in photography. They focus faster and closer, and together with the Nikon F5, they provide performance that's unequaled.
Current lenses in the AF-S category include 300 f/2.8, 500 f/4 and 600 f/4.