This is the one I believe to be the first version of the Sigma 16mm line. It’s quite a big and heavy lens, the Nikon mount is on a chrome ring, hold in place with three screws and the “YS-NI Japan” engraving. It only has a Nikon F-bayonet simulator fork, so it’s sure to be placed in the pre-AI era. No rubber, all the rings are metal. The cap is a big metal one in 2pieces, like all the ones coming after.
“The YS – Yamaki System – lenses used interchangeable mounts in order to meet the growing SLR market’s wide variety of bodies. Unlike many adaptor systems, the YS allowed auto aperture and metering.”From Sigma history pages
Turret filter ring, with L-1a, y-48, O-56, LB-180.
Please note the 2 parts cap. It was made so it could cut a circular image with fissheye effect at the center of the frame
Here is a nice comparison of the lens family evolution, from left to right YS, XQ, and the last filtermatic.
I’m looking forward to some info on this lens history. First of all the exact market introduction date…