NIKON LENSES.. Three main styles of manual focus lenses. 1. Fully automatic diaphragms, and a prong was affixed to the aperture selection ring that engaged the metering system of the camera on which it was mounted. Camera could meter at full aperture, but the lens/camera combination had to be manually indexed to the maximum aperture of the lens in use. 2. AI lenses had a small tab on the aperture ring that engaged the meter on the camera body. No further indexing was necessary. The metering prong was preserved for use with Non-AI camera bodies. 3. The AIS series. These lenses are AI lenses with several key differences. In the context of this review it is sufficient to note that AIS lenses added a small semi-circular notch in the base that enabled cameras like the FA and F4 to identify the fact that the lenses had a linear aperture actuating lever, needed for the programme mode. A sloping ridge on the inside of the bayonet informed the camera of the focal length of the lens that was in use. This enabled the camera to set minimum shutter speed to guard against camera shake when selecting the shutter speed/aperture combination in Program Mode. On most Nikon cameras other than the F4 and FA there is no advantage to mounting AIS lenses instead of AI lenses. AIS lenses also preserved the trademark Nikon metering prong so that they could be used on older bodies.
Posted on: Wed, 26 Nov 2014 08:50:20 +0000
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