MS-Optics Xenomax 50mm f/3.5

MS-Optics Xenomax 50mm f/3.5

Among the standard lenses designed by Miyazaki Sadayasu, the Xenomax stands out for packing a Xenotar-derived optical layout into a body weighing only 65 grams. It is one of the "history series" lenses from MS-Optics, the small Japanese workshop Miyazaki has run since 2006, and it is described as pursuing high correction of aberrations and resolution within an unusually small package [1][2]. The Xenomax is the successor to Miyazaki's earlier MS-Mode 50mm f/3.5, which used a Helia-type formula, and it was introduced in 2022.

Optically the lens uses five elements arranged in four groups, with a twelve-blade aperture and a minimum focusing distance of 0.5 m. It is built as a Leica M-mount lens but, in keeping with most MS-Optics designs, it is not rangefinder coupled, so focusing is done by scale or with live view on mirrorless bodies. Handling is typical of Miyazaki's work: a slim barrel with a short focusing rotation of roughly thirty degrees that suits quick operation, and a 37 mm filter thread that mounts reversed, while a 30.5 mm reverse-thread hood is supplied with the lens. The image circle is large enough to cover digital medium-format sensors of 44 by 33 mm, which is part of the lens's appeal.

A point of confusion worth noting is the later Lumitar 50mm f/3.5, released in 2025, which shares much of the Xenomax's specification sheet. Unlike the Xenomax, the Lumitar uses a retractable barrel, is not advertised as covering the 44 by 33 mm format, and is reported to fall short of the Xenomax optically. At launch the Xenomax was offered in black and silver finishes [3]. Production figures for these hand-built lenses are small, and they are sold through a limited circle of Japanese dealers and direct channels.

Optical qualities

Rendering Reviewers describe the Xenomax as sharp with generally well-controlled aberrations for its size, with performance that looks strong both on published MTF data and in real images. On a 44 by 33 mm medium-format sensor it shows almost no distortion and little falloff across most of the frame, with vignetting visible only in the extreme corners, for example against a clear blue sky. Color is rendered naturally and contrast is slightly on the lower side from raw files, a character that can be raised in processing for a punchier look. Because the design draws on the better central portion of a larger image circle, edge performance benefits accordingly.

History

Development and Launch MS-Optics, formerly MS-Optical R&D, is a one-man manufactory founded in 2006; the initials stand for Miyazaki Sadayasu, who designs every lens, typically with low element counts, no aspherical surfaces, and optical formulas still calculated by hand, with the emphasis on small size rather than maximal correction wide open. The Xenomax 50mm f/3.5 belongs to Miyazaki's "history series" of designs and was released in 2022 as a refined replacement for his earlier MS-Mode 50mm f/3.5, moving from a Helia-type to a Xenotar-type configuration.

Special editions No major factory special variants of the Xenomax are widely documented beyond the black and silver finish options offered at launch.

Collector Notes The Xenomax is closely related on paper to the later Lumitar 50mm f/3.5, so buyers should confirm which lens they are looking at: the Lumitar has a retractable barrel and a 30.5 mm filter thread, whereas the Xenomax uses a 37 mm reversed filter thread and is the design marketed as covering 44 by 33 mm sensors. As with all of Miyazaki's lenses, these are hand-assembled in small numbers, so checking the supplied reverse-thread hood and verifying smooth focus and aperture operation is sensible before purchase.