Sigma's mirror telephoto for Yashica AF — the 600mm f/8 reflex at extreme reach.
The Sigma 600mm f/8 Mirror Lens in Yashica AF mount is a catadioptric (mirror) super-telephoto from Sigma, adapted for Yashica's autofocus SLR system. Despite the Yashica AF mount coupling, mirror lenses cannot provide autofocus — the AF designation refers only to the mount compatibility, not the lens's focusing capability.
The lens uses a catadioptric mirror design providing 600mm at fixed f/8 aperture, Yashica AF bayonet mount, manual focus only, and the characteristic donut-shaped out-of-focus bokeh inherent to mirror designs.
The 600mm focal length in a compact mirror design provides extreme reach for wildlife and sports photography at a much smaller physical size than a conventional 600mm telephoto. The donut bokeh is a known characteristic of all mirror lenses. The Yashica AF mount is directly compatible with Contax AX bodies and adaptable to other systems.
Test manual focus operation. Verify Yashica AF mount coupling. Inspect front and rear mirrors for coating condition. The donut bokeh highlights are characteristic and expected. Yashica AF adapters for Sony A-mount and other systems may be available.