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18
E
Variable aperture/two aperture indexes
(Refer to chart
3
on page 71.)
Zooming the lens from 80mm to 400mm decreases the maximum aperture approx.
2/3 of an f/stop. For cameras with TTL metering, there is no need to adjust the
aperture. Likewise, for TTL auto flash photography with Nikon Speedlights, no
adjustment is required. However, when the flash-to-subject distance approaches
either the near or far limit of the automatic shooting range, the aperture may need to
be adjusted slightly.
When using a separate exposure meter or taking photographs in the non-TTL flash
mode, select the appropriate aperture index according to the focal length setting in
the following way: The aperture index (line) is used for the 80mm focal length setting
and the dot for the 400mm setting. Click stops are provided at the aperture index
(line) for each aperture setting. For zoom settings between 80 and 400mm, align the
aperture ring between the two indexes to obtain the best overall exposure. To
determine the correct aperture, refer to the chart 3 on page 71—Relationship
between focal length and maximum aperture.
Infrared compensation
When shooting black and white infrared film, it is necessary to make slight manual
compensation to the focused distance. With color infrared film, no compensation in
focus is needed. The small gold dot just to the left of the distance index line is the
infrared compensation index at the 80mm setting. First, focus manually on the
subject, then realign your focused distance with the small gold dot. Then attach a red
(R60) filter for infrared photography. To determine the position of the infrared
compensation index at all focal lengths, use this chart.
Focused length Compensation from distance index line
setting (on distance scale)
105mm 4.1mm
135mm 2.3mm
200mm 0.7mm
300mm 0.2mm
400mm 0mm