The Mamyia Sekor E 3.8/70-150mm is a relatively small and well performing 2x telezoom for the Mamiya ZE/ZM SLR series. It was introduced in 1982 along with the 3.5-4.5/28-50mm zoom and three faster primes, namely the 2.8/28, the 2.8/35 and the 2.8/135. While zooms in the 70-150mm range never became as popular as the 80-200 telezooms, most manufacturers were producing such short telezooms during the early 1980s. Some of them are highly sought after even today, due to their excellent performance and small dimensions (e. g. the Minolta MD 4/75-150mm). 

The Mamiya 3.8/70-150mm has a classical [12/9] optical construction which was pioneered by Nikon for the second computation of their 4.5/80-200mm Nikkor (1977). Just a few years later most 80-200mm and 70-210mm lenses would have very similar [ 12/9] or slightly altered [13/10] designs. Its barrel is made completely from metal. A small retractable sunshade is integrated into the lens. The aperture, clickable in half stops, ranges from f3.8 to f32 which is at least one stop further than most comparable lenses.

On 24 MP full frame, the Mamiya Sekor E 3.8/70-150mm performs very well. I have compared the Mamiya side-by-side to the well respected Nikon E 3.5/75-150mm lens which is of similar size and specs.

At f=70 (75) mm and wide open, the Mamyia as well as the Nikon E have a very good resolution over the entire image. Corners are slightly less sharp on both lenses, and stopping down to gradually increases their corner resolution, but that's only an issue if you need perfect resolution ove the entire image e. g. for landscapes. The Mamiya zoom has slight field curvature (corners are very sharp even at f3.8 when you focus on them), and nearly no CAs.

At f=100mm, again, there are slight issues with corner resolution on both lenses (slightly more viosible than at the short end), and stopping down to f8 results in very sharp and contrasty images with both lenses. Nikon E and Mamyia are almost indistinguishable at any aperture.

At f=150mm both lenses, again, perform similarly. Wide open, both lenses have good corner resolution, but lateral CAs become apparent now. Stopping down mainly incerases the contrast.

The Mamiya Sekor E 3.8/70-150mm performs very well and well balanced over its entire focal range, and nearly free from lateral CAs at 70mm and 100mm. Apart from a slightly lower corner resolution and contrast, the lens wide open is as sharp as at f11.

MAMIYA SEKOR E 70-150mm 1: 3.8                 (12 lenses /9  elements)