The situation in 1983
The previous years brought the exposure automatism to SLR, innovation that had been introduced by compact cameras. Beginning 80, the new challenge is the automatism of the focus: the autofocus.
Already some compact cameras offer this possibility and it works. Most of them with an active autofocus, the reflection of an infrared ray emitted by the camera to the subject determining the distance. The passive system works with the detection of phase differences.
In 1982, Pentax has proposed, with its Pentax ME - F, a zoom SMC Pentax AF 35 - 70/2.8 lens integrating an process engine, the mechanism of determination of the distance and 4 AAA batteries to power it. This initiative will be followed by others manufacturers. These lenses are enough expensive, heavy and less efficient.. The solution is therefore elsewhere.
In 1983 Olympus OM30 and Minolta X600 cameras are launched that all two allow assistance to the focus. The module of recognition of the distance is integrated to body but the focus itself resides manual and is not powered.
The Nikon F3
The Nikon F3 has been launched in 1981 to succeed to the Nikon F2. It possesses the automatic exposure a shutter tested for 150 000 cycles, a fast motor and preserves the interchangeable viewfinder, distinctive sign of the F series.
It has also and it is stranger, inside the darkroom some elements whose seem usefulness and unknown. Some people think that it concerns elements for the autofocus because Nikon has repurchased to Leitz (Leica) rights of utilization of the system Correphot.
Leitz has been one of the firsts on the world to develop an autofocus prototype with the Correphot in 1976, adapted to the Leicaflex SL2 and presented to the Photokina. A secondary mirror deviated a part of rays to a mobile pattern (mechanic system !) for an electronic evaluation of the MAP. Correfot means "maximal 'correlation' between two elementary light rays passing by the extreme edges of the ward of the lens and stemming of a same point of the subject. ".
We may notice that 30 years after, Leitz has no lens to automatic focus neither for its of M rangefinders nor for its reflex R.
For its professional bodies, Nikon has always been very prudent and has first introduced its innovations on semi or public camera body.. Thus the pondered measure and the exposure automatism have first been presented on Nikkormat FTN and EL, as later the mode programs and the matrix measure it will be on Nikon FG and FA.
In 1980, the exposure measurement and the automatism are mature. Nikon F then F2 had followed the evolution of these techniques by evolution of their viewfinder. Now the new Nikon F3 can integrate directly the silicon cell and the exposure processing in its body itself.
Peculiarly, this is not on an amateur camera that will be the first autofocus Nikon but a body of the series F itself .
The NIKON F3AF and the viewfinder DX1.
In 1983 Nikon presents an evolution of its flagship camera : The Nikon F3AF with its viewfinder DX1 and its two lenses : AF 80mm f2.8 and AF 200mm f3.5 ED
The mount F is kept and the F3AF preserves the same finish and same accessories that the F3. Lenses AI and AI- S can be used without restriction and benefit of an assisted focus. The main difference between F3AF and F3 is some supplementary contacts that exist in the pentaprism and these contacts are also surround the lens mount..
The F3AF possesses a viewfinder dedicated the DX1 which is huge and contains all the electronics of phase detection. The viewfinder DX1 covers only 92% the image while others viewfinders of the F cover all 100%.. Correct focus indicators or not are visible in the viewfinder and the view screen is special.
This viewfinder contains also 2 AAA batteries that serve to the power the viewfinder itself but also motorized lenses. The small battery button the F3 is being insufficient to accomplish this work.
The denomination DX1 let suppose that Nikon forecast to decline its viewfinder to the fur and to measure of progress of the autofocus. By placing the autofocus in the viewfinder, Nikon authorizes itself to evolve it easily without retouching the F3 body.
The two lenses, AF 80mm f2.8 and AF 200mm f3.5 ED, keep the all metal finish of AI-S lenses but added contacts on the rear mount. The lens motor is incorporated in the lens. They have been chosen because they are two focal lengths wanted by action and sports photographers. The focus is made by displacement of an internal lens that minimizes the movement to do and allows a rapid response time. The system can detect and react to evolution of distance in 0.5millisecondes. The point from infinity to the shortest distance is reached in 0,6 second for 80mm and in 1,7 second for 200mm. These two lenses are announced as firsts of a new series. In fact, there will be follow by other model.
Comparing to the Pentax ME -F , Nikon has left the power and the detection of the focus in the body, it put the engine in the lens itself.
Two year s after, Minolta with its 7000 and its integrated motor in the body creates a new reference and a large commercial success, followed later by Nikon that adopts, as well as Pentax and Olympus the same system. The Nikon AF system has a mount quasi - identical to that the F3AF with contacts in the mount of lenses and on body. However the two lenses AF F3 are not compatible with the new Nikon AF system. The AF-F3 lenses can be mounted without problem on the Nikon F4 but apparently, lose their function autofocus with the other Nikon AF bodies
These two lenses by their design are precursory of modern AF lenses, all of them have a integrate motor. Since 1985, Canon chooses this solution for its new EOS system despite a highest cost and after, all the great marks, Sony, Nikon, Sigma, and now Pentax have placed an integrated motor first in the tele-lense high of range then now for all lenses. The new D40, the last Nikon digital reflex can only receive only AF-S lenses.
F3AF had almost all good but its high cost, as well as that lenses to motor integrated, its small sales have limited the success. If Nikon had launched this system in a public body first, maybe the success will be greater As such, the Nikon F3 AF remains an incomparable camera like no other in the range Nikon.
AF 200mm f3.5 ED
AF 80mm f2.8
viewfinder AF DX1
viewfinder AF DX1 with AAA batteries
viewfinder screen F3AF
Nikon F3AF Specifications