Distance Technology
Since 1992 when the F90 film camera was introduced, a change was also incorporated into initially a small number of AF Nikkor lenses available from that time. An updated CPU to inform the camera at what distance the focus was set at was also fitted.
Image Nikon Corporation
This information is importantly used by a number of our cameras systems from Matrix Metering to TTL Flash exposure control. In essence, it helps provide the more automatic systems with important information so in turn we can concentrate on capturing shots more quickly.
It took a few years before the majority of Nikkor lenses included this capability, and the first were called as a group ‘AF-D Nikkors’. But other groups and generations have also used the same capability, so early on AF-I telephoto lenses, and now AF-S generation Nikkor optics of today for example, also feature ‘distance technology’ capability. It is one of those ‘hidden’ benefits we pay for.
To illustrate how this helps I often on some Speedlight courses remind people that in the past, we had to read distance information off of charts when using flash bulbs or older flash units, as part of the process of making sure we were at the right flash to subject distance for a good expsoure. Thats taken care of now thanks to distance technology so the whole process has speeded up.
