Nikon says that adding autofocus on their 58mm f/0,95 Z would have increased the size of the lens “beyond imagination”
Image of an early mockup of their 58mm f/0,95 Z lens
In an interview released at Xitek Nikon said that they actually hoped to implement autofocus on their 58mm f/0,95 Z-mount lens. But the autofocus was slow and lens size increase “beyond imagination” :)
Here is the google translated text:
Of course we have also studied AF, and driving the focus lens itself can be done. But the action is quite slow, not as fast as manual operation. At the same time, the increase in size is far beyond imagination. It cannot be driven by the existing ultrasonic motor, and a larger actuator must be arranged outside the lens.
Therefore, if you really want to achieve AF in the F0.95 lens, this optical type will not work. You need to reduce the focus lens and use the internal focusing method. But using this method will result in a longer overall length, which means that peripheral components will also increase, and the lens will still be larger and heavier than it is now. Even if such a lens is made, even if the product is very special, it may not be established as a product, so we gave up AF.