Mamiya Sekor E and EF lenses were the last iteration of a long and successful series of interchangeable lenses fro Mamiya 35mm SLRs.
Since the début of their first and extremely rare "MAMIYA" SLR in 1960, Mamiya had prduced a large number of different SLRS using a wild variety of different lens mounts. While Nikon and Minolta did keep their proprietary bayonet mounts introduced in 1958 for more than 40 years, Mamiya right away made a grave mistake when equipping their first SLR with the (then) most common Exakta bayonet: The small diameter of that bayonet soon turned out to be unsuitable for fast lenses as well as for long telephoto stuff. It was replaced by the M42 screw mount at time when it should have been clear to Mamiya that M42 was unsuitable for TTL metering. When Mamiya realized that, they introduced, finally, their own proprietary ES bayonet mount in 1972. However they were late, and unsuccessful. Reverting to a (proprietary) M42 mount which allowed for open aperture TTL metering, they soon introduced a new bayonet mount in 1977 which still had some of the drawbacks of their M42 mount. Two years later, the mount was modified again − and here we are: The Sekor E series of lenses finally made their debut in 1979, together with the fully automatic and low ost Mamiya ZE SLR.
A first series of Mamiya Sekor E lenses was released together with the Mamiya ZE in 1979. It consisted of six primes (3.5/28, 1.7/50, 2/50, 3.5/50 Macro, 3.5/135 and 4/200) plus a zoom (3.8/80-200). Some were taken over from the earlier Sekor CS series (1.7/50, 2/50, 3.5/50, 3.8/80-200); the others were new lenses (3.5/28, 3.5/135, 4/200).
Around 1982 the len lineup had grown to nine primes (adding a faster 2.8/28, 2.8/35, and 2.8/135mm lenses taken over from the CS) and three zoom (adding a 3.5-4.5/28-50 and a 3.8/70-150).
The last lenses added were the two primes 1.4/50 and 4/300 as well as the zooms 3.5/35-70, 3.5-4.5/35-105 and 4/80-200. In addition, a few more lenses with Sekor E bayonet were available from Osawa, the distributor of Mamiyas 35mm SLRs in the US and elsewhere. When Osawa collapsed in 1984 and Mamyia stopped working on 35mm SLRs 8including their mysterious AF SLR "Mamiya ZF"), they probably had other primes nearly ready for release, among the a superwide and a fisheye. Sadly, no additional information ever has found its way out.
