The Mamyia Sekor E 2.8/28mm is the younger cousin of the Sekor CS 2.8/28mm, with whom it shares its optical formula. Both lenses have a rather sophisticated [8/7] lens layout − most of the contemporary 2.8/28mm had only five or six lenses. Notheworthy exceptions were the Nikkor Ai 2.8/28mm and the Minolta MD-I/-III 2.8/28mm with seven lenses, and the AiS Nikkor and the Leica R with eight lenses.

Both the Sekor CS as well as the E / EF 2.8/28mm lenses are tiny and lightweight (165 g) despite of their metal barrel. On 24 MP fullframe cameras the Mamiya Sekor 2.8/28mm performs as good as the Minolta MD 2.8/28mm [7/7], Even the Nikkor Ai 2.8/28mm (7 L) or the Zeiss Distagon CY 2.8/28mm aren't much better.The Mamiya has slightly more lateral CAs, though than the Nikkor and the Zeiss.

An adaption of the E and EF lenses to Sony E-mount cameras is easy. Commercially available adapters e. g. from Fotodiox are available. They are slightly more expensive than most other adaptors since they have a built-in mechanism allowing to set the aperture (which originally was controlled by the cameras themselves; there's no direct link between aperture ring and aperture mechanism on the lens!).

Back in the mid 1980s I've been using this lens extensively for landscape photography, always with very good results; around 1984 it had replaced the slower Mamiya Sekor E 3.5/28mm, which was even lighter, but not as good as the faster 2.8/28mm.

As all the faster Sekor E primes also the E 2.8/28mm is pretty rare and much more expensive than the ubiquituous E 3.5/28mm. Current ebay asking prices (2023) are in he CHF/USD/EUR 200.-- range, but there's not much information on prices actually paid.

MAMIYA SEKOR E 28mm 1:2.8                  (8 lenses / 7 elements)

Below there are 100% corner crops from the JPGs out of the 43 MP Sony A7RII.