Nikon's continued support of the F-mount across the SLR camera range is a well-known
and much appreciated feature, as it allows the investment in older lenses to be preserved.
However, when using an Ai type lens on a D-1, users should be aware that the mechanical
maximum aperture stop sensor (which tells the camera exactly how wide open a particular
lens will go) is not present on the D-1. Instead, the D-1 (and, for that matter F-5,
F-100 and other cameras that can be used with CPU lenses) reads this information
electronically from the CPU in the lens.
This means that in autoexposure mode, an Ai lens is likely to slightly under- or
over-expose, making it necessary to set an exposure compensation for that lens.
Fortunately, all lenses of a particular model will always deviate in the same way (usually
under-exposing) and this deviation will be consistent at all apertures.
If you are using an Ai lens with the D-1, first make a few test exposures and check the
exposure meter reading with the actual result. It should only take a few attempts to work
out the required compensation, which can then be employed whenever that particular
lens is used.
