Here's a chunk of Sigma history, a lens one doesn't come across very often, especially in the company of it's rather unusual designated lens hood. It's the Sigma 28mm Widemax YS f/2.8. When this lens appeared on our local auction amid a conglomeration of other photographic detritus, I was quick to recognise it and pay the very low "Buy Now" price. It has seen quite a bit of use, judging by it's cosmetic condition, but the glass is in reasonable condition. This lens belongs in an era when Sigma was building very high quality lenses; towards the end of the 1900's the marque seems to have suffered a decline in quality and reputation, which it has redeemed over the last decade or so with the production of the great "Art" series. However, in the seventies and eighties some very innovative lens bore the Sigma name, and this was one of them. The Widemax was Sigmas first 28mm lens, and internationally one of the first to feature a maximum f/2.8 aperture. Hence, the "max" designation, I suspect... Released around 1970, the lens sold very well, with photographers attracted to the speed of the lens and the quality of it's images. According to the one-time Sigma product development executive Yasuhiro Ohsone, writing in his fascinating "Oshone's Anecdotes" series, Sigma's then CEO issued a directive that all future prime Sigma lenses should feature a f/2.8 aperture or larger, such was the perceived marketing power of larger apertures. The "YS" designation indicated that the lens was constructed with the Sigma interchangeable mount, not unlike the T-mount system, with individual mounts held in place with three tiny grub screws. The lenses came equipped with a little screwdriver, to facilitate attachment and removal. This example had a M42 mount fitted, and as I have a small collection of Sigma YS lenses I also have mounts for Nikon and Pentax K. Sigma produced "The Perfect Hood" for their wide-angle lenses, and I was fortunate enough to obtain one along with the lens. These are exceedingly rare items and very attractive and well-made, with a flocked interior surface and clamp fittings to fit snugly around the exterior of the lens. The lens is of very heavy all-metal construction, beautifully smooth in all movements and with a very long focusing helical that allows great precision when focusing. The optics were a retrofocus design, in itself a challenge in the 1960's when it came to constructing wide aperture lenses. Here is a diagram, credits to Yasuhiro Ohsone. This formula was repeated in subsequent lens series, right up until the launch of the very successful Miniwide lenses in 1978. I tested the lens on a walk around town with a M42 Adapter on a full-frame Sony A7R camera, a platform guaranteed to expose any faults or weaknesses in a lens's performances. Not many 28mm lens from this era have met my usability standards on the Sony, many of the Big Names falling by the wayside with poor corner sharpness, image stretching or other distortions, but this Sigma performed surprisingly well, especially considering that it's now around 50 years old and definitely in the vintage class. I'll post some samples below. I hope you'll find something of interest.